Fairemail is great. Better than Thunderbird and any other mail client around. Every so often I see a new mail client pop up for Android advertising that it does X better than any other client; I look at it and it's either built on top of either aosp or some other oss email client (or a rewrite of same) with X feature bolted on, often with numerous features missing. If you want a full email client, go with fairemail.

Reminder to take a look at what nontrivial OSS software you use every day that you've never paid for, and consider a donation (I recommend GitHub sponsorship as a method that currently charges no fees to either the donor or the recipient)