> there's still no great way to avoid steadily losing it if you ever leave

That applies even to your original language. ~15 years after moving away, talking to family and friends at home feels... awkward. I can still do it easily, but honestly, sometimes I wish I could use English, even if that's not perfect either.

It's so much easier with friends who also moved out. We can switch to a more comfortable language for each thought or even mid sentence if you prefer a specific word choice.