The Russian invasion of Ukraine has three primary goals: geo-strategic; strategic; and tactical. The geo-strategic goal is decouple Russia from the Western economy and integrate heavily with China and other Eurasia leaning nations. The invasion of Ukraine resulted in massive sanctions as promised by Western powers, and as a result Russian President Putin was able to get his population on board with decoupling. Putin's moves to bolster the Ruble by requiring for purchases of oil and gas is a good example of this. On the geo-strategic front it is clear that Russia has won the war.
The picture is a lot less clear on the strategic/tactical front. On the strategic front, Russia's primary goals are clearly to make Crimea sustainable as an unsinkable air craft carrier that dominates the Black Sea. To achieve that goal Russia must, at a minimum, secure Kherson and Zaporizhzia oblasts (provinces). Unfortunately for Russia, the war in Ukraine has shown that Crimea is very vulnerable if Odessa oblast is not secure. The strikes on Russia's Black Sea Fleet, and air bases located on Crimea make it crystal clear that securing Crimea means securing Odessa oblast. To this end Russia has not put as much as a dent on Odessa, and it must be said that strategically they are failing here.
The other areas of strategic necessity are the Donetsk and Lugansk Republics, which are collectively known as the Donbass (region). The Donbass gives Russia strategic depth on its southern flank which is critical to protecting its underbelly. Donetsk Republic contains massive gas and oil fields (mostly untapped as yet) which a Eurasian Russia would want in its back pocket rather than the West's. For all the above reasons, the oblasts that are strategically necessary for Russia are: Crimea; Kherson; Zaporizhzia; Donetsk; and Lugansk. Another city that is very important for Russia to capture is Kharkov/Kharkiv. Kharkov is Ukraine's largest city and it is located right on the Russian border. As such, Kharkov offers a main supply and logistic hub to any forces (Western included) to invade Russian territory. With the notable exception of Kharkov and Odessa oblasts, Russia has secured, or is securing the remainder of the oblasts. It has therefore been roughly 70% successful strategically.
The tactical picture, however, has been a nightmare for Russia. Starting with the Russian air force. Recall US heavy bombers carpet bombing the Taliban which paved the way for the Northern Alliance to advance and defeat the Taliban (short term). So, where are the Russian heavy bombers and the carpet bombing of Ukrainian formations? Russia has 125 strategic bombers, but is not carpet bombing Ukrainian forces. That is the number one tactical failure. Why is the Ukrainian air force able to still fly planes and helicopters over Ukrainian air space? Russia has 1533 fighter jets, but is unable to establish air superiority over Ukraine. That is the second tactical failure. Why has Ukraine been able to strike Russian air fields, bases, ammo depots, ships, and important bridges with their missile systems? Russian air defence has at least 410 launchers of the S-400 variety. That doesn't include the S-300, Pantsir, or other systems. It seems here that Russia is reluctant to use the S-400 system in an effort to keep that system cloaked from NATO. However, the failure of Russian air defence systems has been a very serious third tactical failure for Russia.
The failure of the Russian Navy to make much if any impact on the war is notable. The Black Sea Fleet has not been decisive in any way during the conflict, despite the fact Ukraine no longer has a navy. Not to mention the Moskva, the flag ship of the Black Sea fleet, that was destroyed by the failure of the aforementioned Russian air defences in Crimea. A fourth tactical failure for Russia. The list goes on.
In some ways it is amazing that Russia has been able to make the progress it has. That progress is largely attributable to the arm of the Russian Army that has not failed - the artillery and missile forces. Russian fire power has dominated the battle space. Other units that have distinguished themselves are: airborne forces; Chechen forces; and Spetsnaz forces to name a few.
In a sense, Russia has been the author of its own tactical failures in Ukraine. It's the old "half-pregnant" strategy that dooms every military in history that has tried it. Unfortunately, it looks like political objectives are knee capping military operations. Russia entered this war because, as US President Biden said, "it has no choice". Ukraine was preparing to invade and put down the self-declared independent republics of Donetsk and Lugansk. Either Russia acted or it watched Ukraine take strategic territory back. It's the "how" it reacted militarily that has caused all the issues for the Russian military since. Rather than using an air war, for at least a month as the US did in Iraq, the Russian military attacked with almost no air war first. That can be considered akin to charging trenches without artillery first...
The initial goal was to topple the Ukrainian government in a lightening strike on Kiev. That is what the columns form Belarus and Belgorod areas were meant to do. The massive forces tied up in this operation, political gamble if you like, could and should have been deployed in the south of Ukraine to undermine the rear of the Ukrainian defences in the Donetsk and Lugansk republics. This is only common sense militarily. The soft under belly of Ukraine if you will. All bridges on the Dnieper River should have been destroyed by air and missile forces, in the first hours of the war, to cut Ukraine in half and deny reinforcement and resupply to Ukrainian units trapped in the east. These are military goals and are not based on wishy washy political gambles.
Whether Putin took advice from others or not, the responsibility for the tactical failures of his military rest on his shoulders. Even to this day all the bridges across the Dnieper River remain intact. NATO is able to funnel heavy weapons and ammo to Ukrainian troops in the east almost unfettered. Without specific intelligence it is hard to determine whether or not the Russian Army argued for a more focused, less political armed intervention in Ukraine. It does, however, have the feel of a political gamble gone bad. It does have the feel of a cat and mouse game, similar to the approach of intelligence forces that Putin once belonged to, than steel fist of a military campaign. In a war of annihilation, which this is becoming, political considerations get thrown to the way side - especially when your geo-strategic goals have already been met. To do less is to show your sworn enemy that you are weak, as evidenced by the massive escalation in Western military support for Ukraine. Weakness, or the perception of it, may lead to all the wolves closing in for the kill.