>>720404407 (OP)
Okay, so
>SC1
a rough but solid initial start, Xbox or PC with the restored patch, but it's still a WIP
>PT
more of SC1 with some minute improvements and starts stuff CT would settle, you can find the full thing for PC on Moddb with a proper patch because it got legally abandonwared ages ago
>CT
the apex of the series, you don't really get any better unless you like DA old-gen, Xbox or PC as there's some patches for PC version to get it working right
>DA
just play the old-gen version on Xbox because it plays like more CT, and ignore the PC/next-gen version if you ever see them because those are pretty rancid dogshit
>CV and BL
they're okay games if you love a hybrid of action shooter and lightweight stealth, but they're not really Splinter Cell games, ports are unified albeit with no more online multiplayer
>PS2 and GC ports
downsized, chopped up, and filled with a lot more loading, ports got better as they went along but OG Xbox version kept the graphical fidelity above them all; if you can't find an OG Xbox old-gen version of DA, then these are a fine substitute as it got the best old-gen port to these two of the generation
>but i just gotta have a game to play of the series between the ones I listed in the OP
If you're up for some old game design that can be a little vague or clunky just to appreciate the medium at its console-ified purist besides the Thief games, then go hit up Chaos Theory and then know the first two games kinda pale in comparison. If you prefer modern controls, a lot more shootan and just want something streamlined and to the point, you can pretty much jump into Blacklist because despite acknowledging past games and especially Conviction, it's reserved enough to be standalone and its own IP almost thanks to the actor changes.