Im doing my best to contact Secret Hideout (it doesnt help that his username is so common when you web search him) but I believe there are no DMs here?

Is there a way for me to contact him (or any other developer) that doesnt imply leaving comments on his products and hopefully expect that someday he manages to see it? (which is pretty much where I am now)

There's no private messaging system on Itch so you'll have to leave a regular comment.

Maybe see if his game/products show up on Gamejolt or IndieDB and see if they have some contact info there.

Check the contact&support page and see if they have a support e-mail added.