GTA 6 modding won't be available when the game releases. Curbing that expectation is part of the job.
What people expect
Custom maps. RP servers. NoPixel-level polish. Mods dropping within weeks of release.
None of it is realistic. Every GTA modding scene has taken years to develop.
What's reasonable to expect
Wait for the PC port. Wait months for tools. Wait months for actual content. Patience is a virtue.