I listened to a few things (not sure if it’s what you had in mind), and really it just sounded like old sample-based synth / ROMpler type sounds, like the Roland JV series and Korg M and T series stuff.
For that stuff, I’d suggest going directly for those sounds rather than trying newer (less “lofi”) sample instruments and such, which imo won’t quite capture it without lots of post-processing.
There are lots of soundfonts out there (these sounds are still pretty popular in video game music and with people into those retro video game aesthetics, which helps), but the best bet might be to demo some of the Korg Legacy synth plugins (M1, Triton, Wavestation) or to do a Roland Cloud trial to try some of those plugins (JV-1080, D50), and see what you like (and maybe sample individual sounds for use outside of the plugins).
All of those plugins will have tons of presets, all organized by type, that will get you these sort of sounds right away (probably a lot of the exact sounds, since many of the players and composers using these heavily were at most just slightly tweaking factory presets). I’d say to start with the Korg ones as well, because they’re excellent and it’s less of a hassle to demo them.
The only thing I’d add in from what I heard is like an Oberheim type synth, or something of that character. Maybe check out the excellent G-Force OB-X VST for that (which goes on sale quite often), or their simplified and cheaper OB-EZ if you’re not interested in making patches yourself. Arturia has some good Oberheim style synths too, but I prefer the G-Force ones personally.
ETA: If you want an actual hardware synth, you can sometimes find old Korg M1s at affordable prices, and they have amazing keybeds. Roland JV1080s are rack mount synths and will be priced all over the place. Occasionally you can get great deals on old Korg Tritons too (especially if you buy local). Many old Roland and Korg rackmount ROMplers that were aimed at a budget musician market or for General MIDI use with a computer can be good enough for these sounds too if you don’t need to tweak things, though they will generally have a more lofi / compressed / dull sound.
A lot of newer Korg and Roland workstation keyboards and similar products will also have some of these sounds, or similar enough ones, and if you aren’t picky about the keybed, you have tons and tons of options there. Maybe demo some in a store and cycle to synth string and choir presets to see what they have to offer.
Other modern things like the Korg Modwave can also nail most of these sounds (as well as many of the more analog synth type sounds).
Lots of options, and if you’re interested in hardware, I can go into more detail. Software is way less of a hassle and sounds the same with these if you don’t need the performance or portability aspect though.
