I haven’t played OG Nemesis, so take this with a grain of salt… but Lockdown wasn’t all that difficult to learn. The rulebook is pretty good and there are decent how to videos out there. From what I understand there are some additions that make Lockdown more complex, but if you’re used to games of this complexity it’s completely doable.
They’re both expensive games, so I likely won’t buy Nemesis, and don’t really agree with buying the original for simplicity’s sake prior to buying Lockdown (if you were leaning toward Lockdown). Of course if you know/think you want both at some point, go for it.
Last Friday got to play Mysterium with a group I don’t usually play games with. Originally was supposed to be The Witcher: Old World, but someone wasn’t able to make it last minute but also had a few new players join and ended up with a higher player count, so I guess it all worked out in the end.
Wasn’t able to get around to any board games this weekend because I was DMing my 2nd session of D&D, so it was still a super fun time.