With the caveat that this is not legal advice:
To be fair on TGF and its 501(c)(3) status: First of all non-profit status is a state level issue in the U.S., not a federal one. 501(c)(3) is a federal tax status. I am not sure why they applied for 501(c)(3) status, rather than 501(c)(4) or another 501(a) status (the range of other 501(c) or other non-profit tax exempt status’), that would be between them and their legal counsel, or at least between them and the service that may have helped them file their organizational papers and helped with their 501(c)(3) application form. If they are denied 501(c)(3) status, it really does not mean much - since my guess is there have not been many who have given to them that gave with the intention of receiving a federal tax deduction. When an organization receives gifts (such as a 501(c)(3) would), and does not have investment income, and is classified federally as taxable, it still has no federal tax liabilities (since gift tax is on the side of the giver not the person receiving, except in very specific situations of recapture - and even then the unified tax credit would cover gifts up to a lifetime giving of $12.9M as of 2023 if the IRS did try to recapture gift tax). That said, I can see a case made for either the charitable category, under relief of a distressed situation until that situation is no longer present, or science under the attempt to correct a peculiar unique problem in the field of computer science. It really depends on their Articles of Incorporation, and how it outlined those.
As far as I know the TGF has received 2 known grants (the first established its creation, the second furthered development of Terra v1 and specific developmental problems or aspects for 2023 Q1). As long as the second is within the purpose stated in their Articles of Incorporation, they appear to be appropriate.
As far as I know, the discussion here, which dealt with two separate items, legal representation/advice for community actions via governance (including for developers), and a structure that can provide ability to handle contracts with the outside world (although it looked at a separate organization as one aspect, rather than other aspects, one which already currently exists - however that discussion is still open although with concerns that as currently proposed, it could end up consolidating influence which could be used to bypass governance). Under that discussion, it was suggested that TGF be dissolved, and a different organization by established (not that it be moved - “U.S.-based Terra Grants Foundation will be dissolved as an entity and replaced by the offshore foundation company”).
I am concerned where there are some that no matter the spend proposal - they keep painting them out as scams when they are not (not saying you, but just noticing it in general).
Just thought I would point that out.