Is it good to add a different niche video in different niche channel ?

my question is as the title states.the thing is there are some trending stuff on hiwch is very hard to build a niche on so i thought that the right thing is to add it to an already existing channel although they are not the same niches.What do you think ?

Does it affect your rpm somehow ? or it is best to keep the channel directed twords one niche only.

If you create channel only for that niche, it will be more proffesional obviously.

I would say its best if you keep a channel for one niche only but testing is everything my friend.
You can give that thing a try you wont lose anything and who knows if you get some outstanding outcomes.

Thanks Guys for the Reply. So more professional means more advertisers investing or what ?