The administration is more fearful of domestic political outcomes than they are the Russians. Most (actually democratic) leadership groups are almost always more afraid of the domestic political blowback than the enemy.

The enemy can only kill you. ;) The domesstic politics can get you out of office/graft/influence/power.

The US lets people get away with shit because there is no domestic political will for action (and they know it) barring direct attacks on the US homeland. When a good quarter of your population is on the side of the enemy (for various domestic political reasons), you tread carefully. I think it is less "if you have nukes they let you do it," and more, crap doing something could cost us the next election.

There is a narrow path to tread there, and so far Putin has done a pretty good job treading it (and fostering domestic political problems in the US).

The Russian military is probably better now than it was at the start, simply because of experience gained and the various revelations of incompetence and corruption. It doesn't mean that it is great.

Russians have always been mass-oriented. It has been their go-to "strategy for basically forever--while the US (post industrial revolution) has been about machines fighting.. and the developments we have been seeing are kind of in our sweet spot, once you get past the traditional reluctance for military leadership to embrace change (especially when that leadership love being pilots and pilots are going to be among the first replaced).