The west feared the Russia military and generally considered them the #2 military on the planet. Joke I've heard lately is that Dec 2021: Russia had the #2 military on the planet. April 2022: Russia has the #2 military in the Ukraine.

It also seems that Russia underestimated the impact on NATO. Now multiple countries are increasing military spending, several countries are now looking to join NATO, and the supply of weapons to the Ukraine is substantial. The current gen anti-tank weapons are so good that even a few hours to a few days of training can allow a solder or two to take out a tank. Sure intelligence on where the tanks are is helpful, but the Ukraine citizens, foreign powers with satellites, and heavy use of drones have that handled. It's amusing to think of a 1-800-got-tank hotlines causing serious problems for Russia. Keep in mind the GDP of countries helping the Ukraine is on the order of $40T, and Russia is $1.5T. Sure Turkey, India, China, and others are receptive markets, it's unclear how many soldiers and weapons they are going to send, especially since they do not want to lose access to the $40T GDP worth of market.

So Russia's advantage in tanks has largely been offset by anti-tank weapons and attacking supply lines. As a result armored vehicles have been withdrawn from various cities. Russia also has a substantial advantage in artillery and missiles, but the reports I've seen who that they are close to burning through their inventory of usable equipment, in particular ammunition and missiles. Apparently quite a bit of equipment is out of order because of the lack of preventative maintenance and production isn't anywhere close to the current burn rate and inventories are dropping precipitously. Sanctions are hurting their ability to produce, the only tank factory in Russia went idle in March for lack of parts, not heard if that's been fixed.

I do think the pending attack in the East will be more difficult for the Ukraine. Shorter Russian supply lines, lessons learned on the Russian side, and heavier dependence on completely destroying cities before invading will make things harder for the Ukraine. But lack of training, calling in the reserves (which aren't trained like the a weekend a month/2 weeks a year reservists elsewhere), and lack of preventative maintenance aren't easily fixed.

Much will depend on how generous the west is with larger and more sophisticated systems like longer range missiles, better anti-air weapons, tanks, and artillery pieces. I'd say currently Russia is no way going to take over the Ukraine, and even just encroaching from the east to take over a few cities is far from certain.

It's looking like the invasion is likely to be one of the biggest blunders of the century. In particular Germany, Finland, and Sweden have made it a priority to increase military spending and provide a unified opposition of Russia. Collectively just those 3 countries have about 3x the GDP of Russia, before the sanctions. Keep in mind Russia can't go all in on the Ukraine, they have to defend various borders from countries they have taken land from, in particular Japan (which all alone has 3x the GDP of Russia) seems quite interested in taking some islands back.

I wouldn't want to be Russia right now.