Going to be an odd one to throw out there given its MMORPG. But Elder Scrolls online is a massive world and 90% of the content can be played solo. There is a massive number of quests, stories etc and quiet enjoyable from a PvE perspective.
That's part of the experience surely, what questing experience are you looking for? It's not a race.
I often see Fallout:New Vegas mentioned in these threads, and it's one of the very few of games listed in previous posts I've not played. As it might be relevant to the OP's interest too - is there a good guide for what to install mod-wise to bring the graphics (and any QoL improvements) up to modern standards? I don't mind old-skool graphics in isometric RPGs, but for a first-person game I keep thinking how dated the vanilla version of this looks.
I'm really enjoying Bards Tale IV at the moment - probably not the best game ever made but worth it for the nostalgia element alone if you grew up playing the originals!