If you want a gig like that, costume clothing, furniture, wallpaper and flooring for Sims 4. While there is somewhat of a community thing and the TOS about only having paid early access of a reasonable time, a lot of creatures don't, and big chunks of the community will bend over backwards to defend it. So if you put out some paid stuff a lot of people will pay for it. If you don't reales it for free after some time, big parts of the community will be mad at you, but many creators don't follow that code and you can choose between putting up with it or just release it for free after sometime frame you are comfortable with, community stand is a month but ones again a lot of people don't follow that and have lots of people buying their stuff.

And also if you just put out relatively good stuff, you will get a huge bonus over other people, even if you are paid only or have longer than community standard times. Because a lot of Sims 4 cc (in the Sims community moded assets are called cc while just mod/mods means gameplay mods) is really bad, with chep asset flips, theft and just really badly looking and functioning stuff and that includes quite a lot of the paid only scene. So you know the bar ain't that high.

If you want a in game or developer official option, keep an eye on the upcoming Project Rene it's the next sims game / sims spin off and while it is not confirmed to have paid cc and mods, there is a high likely hood of it.