I'm just not sure what the SRD and associated license actually protect against. If you can't copyright mechanics, and assuming you write your own text for any particular thing, what do you need any sort of permission for?
Leaving aside the issue of using words which WotC invented (e.g. "tojanida"), the OGL is essentially WotC's pledge not to pursue litigation against you if you stick to the terms of the license, i.e. you can use anything in the SRD and not have to worry about being sued for copyright infringement.
The thing about "you can't copyright mechanics, only their artistic presentation" is that the practical implementation of that rule can be hard to parse. I attended a lecture on this very topic by an IP lawyer at Gen Con 2024, and he pointed out how you can't copyright
f(x) = [(y-10)/2], but you could
possibly copyright Table 1 on page eight of the 3.5 PHB, which lists out the results of that formula (which calculates ability score bonuses).
And that's what the OGL is really all about. Figuring out what's infringing copyright and what's not ultimately comes down to what a judge decides, and getting there can take years and cost a small fortune, because copyright law is complicated. The words "wizard," "potter," "boy," and "harry" are all in the dictionary, and can't be copyrighted by anyone, but if you write a story about Harry Potter the boy wizard, you're that much more likely to find yourself subject to a lawsuit, because a particular arrangement of non-copyrightable materials is something that can be itself copyrighted.
The OGL was WotC saying "we'll let you use all of this stuff in the SRD, and won't sue you so long as you follow the few restrictions in this license," dispelling the fear, uncertainty, and doubt that kept people from undertaking what
might have been non-infringing uses of copyright to begin with. And it worked very well for over twenty years before WotC destroyed that goodwill for no good reason.