I suggest Arclight, its a mod & forge hybird that has high compatibility, new versions that are pretty stable, and has versions from 1.14.x to 1.19.x, I've heard really good things about it and I think aternos users would benefit from another hybird that's also really good, since some setups work better on different hybirds.

(I used the search function, the only response I found was the aternos bot closing the ticket with no response due to no activity for a month)

Well yes, bukkit and forge were never made to work together, but arclight is also a lot more ahead in newer versions like 1.19 and 1.18, the only hybird on aternos (mohist) doesn't work with mods or plugins on 1.19, and doesn't have plugin compatibility on 1.18