I really like Fastmail. It’s just - clean and lightweight. It loads much faster. Has all the features you actually need. No mystery meat. And the UI doesn’t churn every few years for no reason.
You're probably not going to like my answer — I swapped to Hey shortly after it came out, and I'm very happy with it. I check my choice every now and then; recently taking a look at Tuta and Proton. Tuta just isn't there yet, and Proton is just Gmail but in Switzerland. Meh.