changing niche

if i change my niche from a game to another popular newer game. should i make my previous videos private or even delete them?

its about 40 videos i don't get much traffic from them and i feel like they will hurt my ranking for my new niche

or do they have no affect what so ever?

my reasoning is if i get any views from the previous videos and youtube decide to recommend my videos again to the same viewer.
and its not the same game they will probably either not watch or just watch for a few second then click off, ruining my watch time retention.

Just how different are these games?

I suspect they will have some crossover audience and therefore I would keep them up.