Mutt - which webmail providers work well with it as of 2021?

All in the heading there but despite more glamorous options I've using Mutt for email increasingly, on my three deliberately bling-free systems. For a long while I could not get Gmail to work with it but now it is. My main email address is with Yandex, and I have ones with Yahoo and Protonmail. I wouldn't expect Protonmail to work with Mutt and I haven't found Yahoo to work, despite modelling my config file on the Gmail one.

If someone here is using Mutt and has found providers that work with it without issue I'd be pleased to hear of which ones they are, ideally with an obviously redacted copy of your config if at all possible.

(I'm using Debian 10.7 built on the netinstall with an Openbox setup that's 9/10ths of the way to LXDE.)

Thanks.