I really don't think it's going to matter that much.

I personally have done the same thing and most of mine are flacs converted to 320 kbps mp3. I've done some opus lately. I can't tell the difference.

I have a Samsung phone soni get a better codec, but it's fine.

I'd probably not go any lower than around 256 kbps personally. If you couldn't tell a difference with Spotify settings you probably won't here either.

Don't stress. Just enjoy. You can always change it later if you think you need to.