GTA 6 will officially get support for custom content. At least a lot of things point to it... But not everything is as good as it may seem at first glance. Rockstar is likely to tighten the rules of modding. Read more details below.
Rockstar is calling out to modders... but with conditions
The company has started actively looking for employees to join the team from the beginning of 2024. In the job descriptions you can discern similar phrases: “user generated content” and “creating innovative game experiences”. We can assume that with a high degree of probability, we are talking about GTA 6.
It's also hinted at by Rockstar's recent purchase of modding platform Cfx.re. There are already leaks in the network that the company has actively started working on a new platform for GTA 6, which is codenamed ROME (Rockstar Online Modding Tools).
Limitations of modding

Also on the Internet walking information that Rockstar engaged in the development of official tools for the creation of mods and custom content. And, in all likelihood, with support for consoles.
There may be a mod store, which can be integrated into GTA +. Perhaps introduce a paid subscription, which will be available custom content.
However, we should expect some pretty tight restrictions, because as the history with Take-Two and modders has shown, behind every opportunity there are limitations. Since the purchase of Cfx.re, the platform started to change: third-party assemblies, real branding, 3D models from other games and even the use of unique models without the consent of the copyright holder are forbidden.
Following from this suggests that modding GTA 6, can be only within the approved tools and under strict control. It will not be possible to port maps, take as a basis for the creation of mods old models or transfer them from past parts of the game. As of 2019, the internal agreement has been amended to prohibit this. If these rules are not followed, Take-Two reserves the right to completely revoke any permission if it sees fit.
A prime example is the smart NPC mod for GTA V's single-player mode. Its author was not given an explanation, just deleted the video and blocked the account. Although the mod did not break anything and worked normally. A similar story happened with VR-mods from Luke Ross. Even if players had a purchased game, Take-Two still banned the mods. The company wants to control its ownership and get monetization, that's probably the reason.
It's as if Rockstar is saying, "You want to make mods? Do it. But only the way we say."
Complete freedom, unfortunately, will not happen. Everything depends on the interests of a large company and money. We can only hope that the new 6M platform will really become convenient and interesting - and will give modders at least some space for creativity.