Looking at the site in the OP, yeah, the last three D&D articles are hastily written listicles full of ads. I mean, 5 Edible Magic Items? I guess they get the clicks.
Pointless listicles get clicks. It's that simple. It's not just D&D, it's everything. Whatever you interest is, the most popuar articles are bland listicles with no substance or value. shrug
For compatibilty purposes, the most likely issue is going to be action surge.
What O5E subclasses require action surge, and is there a simple universal change we can make so they work?
I see since he got banned from here he downgraded his opinion of Level Up from "I like it but my definition of compatibility is this exact thing" to "I HATE EVERYTHING ABOUT YOU!"
Sadly, it's not actually illegal to donate to your own campaign, even if you do it under various dumb names. You can donate to your own campaign as much as you like. It's other people donating to you where the rules apply.
Yeah, that's a weird part of the OGL. It says clearly that by using OGC you agree to the license, but that clause is in the license and therefore doesn't apply until after you've agreed to it.