Okay, I think I finally figured out a solution to the problem of finding new recordings by solo singers. The problem being how are you supposed to find these recordings if you don't already know the name of the performer beforehand? Searching something like "mozart lieder" isn't as helpful as you'd might think.

Anyway, my new tactic is looking up great recordings of a piece with a solo part (eg Mahler 4), noting the singer, and looking up their stuff. So here we have Kathleen Battle, found from the Maazel Mahler 4.

https://www.youtube.com/watch?v=KFCT455mSdE&list=OLAK5uy_l0ykcGky6VOA_5THDlgtUYvI5Shj9aRbA&index=1

But yeah, trying to search up "handel songs" is useless, so if anyone has any recommendations for more recordings like this, I'm all ears!