IMAP, POP3 is the way for me. Use Thunderbird or whatever your favourite email client is.

Use Gmail with alternative email clients, use e2ee so Gmail can’t scan your emails content, consider self hosting your stuff, I’m daily driving a selfprivacy.org instance and I’m quite happy with it.

Gmail has basically established a monopoly on email… Which is bad, but it’s an open protocol so there’s a way out!

I use proton mail. It’s not ideal and I considered going back to gmail but then I opened gmail and I remember why I left. The UI is unusable to me.

Until completely degoogled, the best solution is to use the Gmail account exclusively for Google stuff and nothing else.