I am not a lawyer. Consult legal counsel for legal advice. This is just my understanding of it.
You are comparing apples to oranges.
- The DM's Guild = Pathfinder / Starfinder Infinite. These are Content Creator programs, protecting the originating company's IP.
- OGL = ORC. These are open licenses determining the legal uses of the open content declared under the licenses.
The rules for the Content Creator programs are designed so you can (as a creator) make things in those company's IP (aka settings). They are tightly controlled and frankly, have nothing to do with open content. You must abide by the rules in those programs strictly.
The rules for Open Content strictly forbid you from using ANYTHING protected by a specific declaration of product identity.
To summarize, you can publish a work using the ORC license to make a game powered by ORC open content. You could create a setting for PF2ER and adventures, etc. in your own original setting. You can use the rules not the setting stuff.
The terms of the DM's Guide / Infinite programs are 50/50 split. If you make your own games using ORC, you get a 30 / 70 split with DTRPG (do they still do the 20 / 80 split if you carry DTRPG exclusively?).
I imagine that once more material is available for PF2ER, Paizo will switch the Infinite program to using the Remastered rules, but with the same restrictions. I'm guessing they want the momentum of a "core set" of Remastered rules to outweigh the current rules. Likely to prevent confusion in that marketplace (which version does this work with??).