Thank you very much for your answer. I see the discrepancy now. I also see it as odd that the link from the “official” eelo install page only links to versions compatible with Nougat. That’s unfortunate.
After your response, I decided to play a little and went to the test build forum and flashed the unofficial ROM (from 27.01.2020) of /e/. It seems to be working just fine for now (no sound or button issues, bluetooth and wifi ok), and on recovery reboot TWRP has stayed installed. Looks good!!
-thanks again