Ok,so first off, gta and red; gta is arcade, red is realism. gta has no limits on its creations, red is limited to historical facts, happending, atmosphere and events.
Are there alot more that could be added to red? ofc but sutch development takes time. Afterall, gta5 is 7+ y/o, red is 2. Red had covid in the middle of its existance while gta saw a natural drop in new content cuz they at the times had notingng new to add, and that was before covid forced workers to stay home.
For Red, they have to think hard about what can be added, plus it seems they have taken a stand that the game has to "naturaly evolve". That was atleast their idea to why we did not have houses to stay in from day1.
It allso took more then 6 months when red online finaly was relased to it became playable due to the devs under estimating how toxic and shitty the online servers became when they had a gameworld with no rules, so alot of dev time went down the drain there.
All in all Red is nothing but a test server for GTA ideas and it shows. Further on, if the rumors are true that Red 1 is beeing remade for ps5, then that wont help Red2 online, it is prolly more then 20 years timeline difference between thouse two games, so they cant share online worlds, all it will do is drain dev manpower from Red2 online.