The discussion around online modding has been separate from that of single-player modding throughout the history of GTA. Rockstar's position has always been consistent - we walk through it.
Major ban waves
Recurring waves of cheat bans since GTA Online's inception. Exact dates matter less than the pattern: when cheats become prevalent, Rockstar bans users.
Bans have generally focused on cheaters rather than mod authors themselves.
How this affects GTA 6 expectations
Expect the same pattern. Online modding will not be tolerated. Modding in single-player will likely be left alone.