How much of a threat does Russia's Pacific fleet pose to the US?

The Russian military will never be what it once was. The Federation is weak. The leadership of the Military , though knowledgeable don't have a Disciplined , Trained , dedicated Ranks under them. Too many decades have rotted any Military bearing the Troops had or may yet be holding onto. Too much grift/ abuse/ armament in disrepair. The enlisted ranks are Rife with bribery/ blackmail / greed / sadistic treatment of lower enlisted, ...
The situation is just FUBAR .
Putin is hyper to keep moving and not staying in one place too long, he has to remain unpredictable in where he'll appear and limit time there, sincerely and honestly , he is NO ONE to mess with. As always. But Russia may see a minor re-genesis of some of their past glory of their Military. But , it is nearly without a Doubt the subordinate of the Chinese Military.

The fact that they are now China's "junior Partner" makes this a bigger issue than it was.

The only portion of the military that has real operational experience may be what functional submarines they have left. The surface fleet has never been a major player anywhere but the Baltic and North Sea. Hell, they can't even make their carrier Kuznetsov (sic) function properly. That said, we can't take them lightly.