>>1531408Amagami is a classic, and a very well-polished "true" dating sim where there's a bit of a puzzle aspect to it if you're juggling girls/trying to make sure your non-targets don't end up utterly miserable. Not on Steam, but there's a translation patch. Well-known, but still a hard recommend if you haven't played it already.
Not a dating sim, but Princess Maker 1 and 2 will keep you busy for a while if you're into raising/ruining your very own fictional daughter. They're a passion project by old Studio Gainax, and the attention to detail and aesthetics really shows in these old games.
I have a huge soft spot for Galaxy Angel and Sakura Wars. They're basically playable 2000s action/scifi harem anime, and the vibe is really on point. If you have any nostalgia for that genre, these games really scratch that itch without just defaulting to a standard highschool setting. While they're not "true" dating sims (i.e. stat-raising, navigate the girl's route), they do have actual strategy gamplay to them as well.
For less dating sim, more VN-style dating, I can add to
>>1531628 recs Majikoi. Very enjoyable group cast and off-beat girls. It has the benefit of focusing more on the individual girls rather than an overarching main plot (like more well-known, story-heavy VNs), making it closer to a dating sim.
Give the OG dating sims like Tokimeki Memorial a try too, if you can find them. Many are more like proper "games" than you may initially give them credit, with a bunch of stat and time management autism to get into some of the challenging routes.
As a general resource, vndb has a pretty good tagging system you can also dig through for other stuff that might catch your attention.
https://vndb.org/ 
