In FFXIV, I’m in the post-Shadowbringers DLC content. I’ve taken a bit of a break from the MSQ to get the Nier-themed alliance raids

Are you me? I'm just a bit into the post-ShB patches, and I just finished unlocking all three Nier raids. They're really fun (although I agree: challenging). If you happen to be on Crystal DC and want to party up for some raids or something, lmk!

Think I might try a healer class next, just not sure which one

As someone who is very much a non-healer main, I quite like Sage. My first healer to 90 was actually Scholar, but a lot of that had to do with the fact that I was really into Summoner for a while: when I'm going to heal I usually hop on Sage.