Making a $10/month option isn't too much to ask. Give them an "NIL EliteDawg" title under their username to start with. You'd be surprised with how many would sign up for this. And pin a post at the top on how much the monthly dues are given to the NIL each month to encourage more to sign up for the $10/month option.

Merch and other benefits can be added down the road. I think starting small and growing would be the best option here to avoid sticker shock for a forum that's been free for a decade now.

I'm willing to help and support in any way.