I’m not really sure what you’re asking since your post is a but unfocused, but if your problem is that you have too many addresses with different providers you could simply redirect mail from alternate addresses to whichever one you actually check. When I switched to proton I didn’t delete my old gmail account, I simply imported my old emails and set up email forwarding (see here for Proton’s migration instructions from Gmail). If you want to completely de-Google you don’t need to do it all at once, just migrate accounts to your new addresses as needed.
If you want a separate account for your PC then this does of course require a separate account. There isn’t really a solution there since your problem is also your requirement. You could set up separate folders or aliases for your PC and phone but that might not have the same level of separation you want.
I’d recommend switching away from Chrome-based browsers entirely anyway due to Google forcing through questionable standards by throwing their near-monopoly around, but using one Google service doesn’t mean it’s pointless to switch away from others. You don’t need to do everything at once.