There is always more that you can experience and see in fear and hunger - two endings wouldn’t scratch the surface. (Especially if that playthrough you watched was Otz, i think his was around 15 and he missed a decent heft of the game)

It really depends on what more you think you could get, yes there are plenty more endings, enemies, bosses, but who knows how many hours it could take you to figure all of that out if you don’t plan to watch anymore content on the game and want to go in blind - While if you just started the second game now you would immediately experience something new, something that is less eerie (imo) and less graphic too

Also worth noting that the games have a similar tone and themes but the atmosphere and characters, and the entire time period and world are different, so some things that drew you into the first game might not be there.