The guy sounds harmless, but weird. I would ignore him, I'm sure everyone else is.
Everyone is getting all freaked out because there is some semi-sexual overtones to his suggestions, but in reality he's no different than any other hyper-focused unbalanced individual, of which there are plenty. He's no different that some viewer on a tech channel going "Review record players!" or some such nonsense.

It's your channel, not his. So you should do whatever you want, but I do think you need to have a thicker skin. You admit in your very first paragraph that you are burned out with your production schedule anyway. So perhaps you're more sensitive to this guy and his annoying requests that you should be because you're already on edge. So it sounds like banning/blocking him is the least of your worries.

Because you have perhaps 16k subs. Imagine how many versions of this guy are going to exist when you get 100k subs, or 500k subs. You're going to have to come up with some kind of mental defense mechanism that allows you to exist in between the extremes of going out of your way to appease them and banning and blocking them all. Weirdos are a part of life, and the more popular you get the more weirdos you'll have to deal with.

My advice, contrary to most here, would be to start practicing now.
Perhaps you can have a generic statement ready that you can reply to all of his repeat requests.
One of these corporate non-committal, non-threatening brush offs like:
"At this time we have no plans for content of that type".