You're in for a treat, start with Diablo 1.
Thanks to it's color palette, it's still very atmospheric, even today. There's HD mod that not only makes it no hassle to run this on modern PC with higher resolution but also adds ton of content that was originally cut from the game. It even adds re-imagined cut content that was only just mentioned somewhere in-game or was planned for Diablo 1 but actually ended up being part of Diablo 2 later on. Purists will whine about too many balance/item changes, it's worth it to try the game firsthand. https://mod.diablo.noktis.pl/download
The mod adds one more difficulty level to the base game, so there's room to keep grinding and making progress if you get into it.
I'd say roll Sorcerer if you just want to finish it and move onto sequels. Sorcerer will be pretty chill to play up to the third difficulty. Pick a Warrior/Rogue if you want the challenge, those classes are gear dependent. Since you can trade gear between characters, actually playing the game as Sorcerer and funneling gear to the other classes is a viable strategy to tackle the fourth difficulty.
This is great advice, looks like sorcerer is more my jam. I don't have that much time to think very deeply about my builds. You have been really helpful, thanks!