There was a bundle of Corpse Party old and 2021 edition, but now it is gone

New to the series, what game do I start with? Which ones are the remakes?

I've just finished watching the anime and i really liked it, i decided to play the game to see the true plot, so which version should i start with ?

Hi: I'm going to buy the bundle with both since it's cheaper than buying the 2021 one anyway. But I was thinking of first playing the old one, then the new one. And I saw in the reviews someone said that the original PC one didn't include the CGs from the PSP version. Is that true?? And if it is true then if I play the 2021 one instead will I miss anything storywise or it's a more complete version of the game? As in does the 2021 version include everything that the older version has or is it missing ...

Do either of the two remakes on Steam have the original PC-98 graphics available? If not, are there any mods for this?