Russia's primary problem is going to be the instability that comes out of the reveal that Putin is a typical incompetent authoritarian and Russia's military is weak (and there's nothing they can do about it, clearly, or the past decade of 'modernization' and spending would have). To the extent Russia has had some limited stability under Putin, it has been built on the image of Putin's competency as a command & control operator of the Russian state and Russia's supposed potent military strength in particular - the projection of strength generally, all the fake imagery the propaganda machine has dished out regarding Putin over two decades. Naturally, as it turns out, the truth is closer to the opposite. It always seemed a distinct aberration that Russia would manage to somehow maintain a competent, potent, relatively well-organized military while everything else was so subpar and rotting. Everything makes sense again, their military looks like the rest of the nation.
The knives will come out for Putin now that everybody knows he's weak and fragile. His recent moves to punish powerful internal figures will force him to go even further. Being likely paranoid as dictators commonly are, Putin will likely do as much damage to Russia's internal functioning as sanctions do from the outside to its economy. Putin is likely to elevate the fascism to the point where their system stops functioning much at all, including their domestic economy. Purges, gulags, genocide, things typical of later stage statist regimes, it's all on the table if Putin's intention is to retain his present power. Putin only has two choices: give it up, or kill lots of people to try to fend off the sharks that will inevitably come for him and challenge his position. The considerable, fake image of strength was previously making it largely unnecessary to go as far as most dictators do to retain control, that luxury will now vanish and it'll dramatically damage Russia. People fleeing Russia are making the right choice, get out while you can.