As a Russian, I’d love to tell you that there’s hope, but unfortunately I agree. Integration is not as simple as “you’re in the EU now”, it will take time.

Frankly, the best way to approach it is probably leaving Königsberg / Kaliningrad be as its own state [1] for a bit, and do whatever EU integration programs do. If it works out, you’ll get a million Königsbergers who are a bit nostalgic about Russia but want nothing to do with it otherwise.

One final thing I’d like to note is that the “alien passport” approach taken by the Baltic states mostly, well, alienates the titular nation and Russians right now. If the path to integration was more clear and Russians born and raised in, say, Latvia didn’t feel like second-hand citizens, they wouldn’t really want to have closer ties with Russia either.

[1]: disclaimer for the эшник reading this: this is in a hypothetical scenario where Kaliningrad does get separated from Russia as a result of the “special military operation”. please don’t hurt my family