The surviving Russian pilots are pretty competent at this point.
The surviving Russian pilots fly towards the front line at a high altitude until they get close to the suspected range of Ukrainian air defences, drop glide bombs and then turn around. Sometimes the Ukrainians have snuck an air defence unit closer to the front lines without it being detected and the pilots exit the category of surviving Russian pilots.
I'm not sure how applicable this would be to a confrontation with European countries. Russian fighters will get getting lots of flight hours on CAP as well, but not much combat based on reporting. Both sides are keeping everything inside their own AD bubbles.
But there remains a question of quantity and determination.