Same frustration from me. PLEASE restore the custom font selection!
I have used EN for more than 10 years, just upgraded recently to 10.15, and it is horrible and is shocked to know about EN now restrict us to use a fixed font list. (It's funny that the web editor I am using to type this reply provides more fonts (and more usable ones) than the EN provides).
Many of my notes were edited continuously over many years, and with the new EN it means my notes now has mixed fonts (old + new) in there, which make it hard to read, not to mention some of the fixed fonts picked by EN are bad (e.g. the bulky monospace).
I think there are more than enough customers who complained about this here. PLEASE FIX THE PROBLEM!