Baldur’s Gate 3. The default party size is 4. In single player it’s filled with NPCs. Might be a long commitment, but it’s a bloody good game. If you are more than 4 you can increase the party size with mods that can be installed from within the game. You could increase the difficulty to compensate.
Incidentally the first two games can be played in multiplayer as well, with up to 6 people. But although they are awesome as well they might be a little bit dated.
If you’re looking for F2P Path of Exile is one of the best. It’s an action RPG like Diablo (which is also great in multiplayer).
Darkside is considerably harder. It’s easier when you finish Clouds first but you quickly reach a point where it also gets harder. I think a balanced party composition is also even more important.
When I was a child I didn’t understand that it was turn based. So whenever there was a monster I rapidly clicked the fight button without much regard to strategy. Made it even harder. Don’t think I managed to beat either game back then.
For the hardest dungeon you have to solve a crossword puzzle. In the game you can read a long story that contains all the answers but the puzzle is in a huge labyrinth far away from that story and it would be too tedious to change back and forth between the two.
The manuals of the games (it’s actually two games combined into one even larger game) have dedicated blank pages for notes at the end. I also had the way to the boss of the second game written down there.
Back then it was quite common for RPGs to have space for notes in the manuals.
I will probably buy Horizon Forbidden West for my son. Told him to wait until it is discounted. But 40 € is still very much the full price of many other games. And we already bought all the Christmas presents this year. Decisions decisions.
At least I’ve still got a few more days to decide.