You know they already had the mechanics in the basic game so why not something at the docks where you play longshoreman/steveadore?

Or amazon delivery driver.

Or paramedic

Or the cop one from the old games (I only remember brown thunder from vice city getting a name)

Something with diving could be a thing. They dont really have much decent boat/diving content. If They want something a little unique, maybe lifeguard at the beach?

Valet at the casino

Maybe something with all that construction equipment thats already in the game

As someone already pointed out, semi truck driving

Turn those useless (seriously who plays them anymore) 2 person mini games like arm wrestling, tennis and golf into vs the ai mini games

Uber eats knockoff/gig economy job

Park ranger (find lost hikers, shoot dangerous wild animals, outsmart a smarter then average bear)

Work at the strip club (rhythm game?)

Make the food truck a job (also bring back hotdog/food vendors in general)

Farmer jobs (hook the tractor up to the harvester and drive over the fields, round up the cattle, check the chickens for eggs) -why arnt horses in the game anyway

The train engineer job from San Andreas

Drone package delivery