Hey there @Supreme - I wrote about this in your other post, so I will just link it here:
The policy you are referring to is below, and it pertains to Gitcoin proposals. Not grants rounds.
Find below Gitcoin Grants Program General Eligibility Policy & related information to the round specific information. As it read it, it does not prohibit donors from contributing to their own project, or projects they may be involved with.
https://gitcoin.notion.site/Gitcoin-Grants-Beta-Round-Eligibility-b7fca9fd3c26450b89ded11caaa6497f