I have the feeling that you are already that far off from the "core rpg", that at this point there are basically hundreds if not thousands other rpgs you could buy. Not that this is a bad thing. In the end it might be easiest to just go through the RPG-watch recommended list and see what you could like from there.
https://store.steampowered.com/curator/4973374-RPGWatch/#browse
Even though there are likely tons of other games missing in that list.
Dark Quest 2 for example. (can recommend)
Ash of Gods (not played)
Avernum 3 (can recommend)
Battletech (not played)
Dead in Vinland (not played)
Tomb of Annihilation (not played)
and likely tons of others