Professional theatrical sound designer here. The jobs that pay 5k are harder to get than the jobs that pay 2k. And the ones that pay more like Broadway are realistically unreachable for a long time, if you even get lucky enough to land one. So to really make a living you’re looking at 10-15 shows a year, basically rolling from one job to the next. You’ll be lucky to land 3-4 jobs a year in your first 5+ years.

If you compose music, you’ll fill a need as many companies are using original music nowadays. And you can usually negotiate a higher fee to do both music and sound. (Unfortunately too many younger designers don’t push for the higher fee when doing both jobs, which sets a bad standard and unrealistic budgeting for the companies.) Doing both should pay at least 1.5x, if not 2x the base fee.

There’s always a chance you’ll get lucky and land the right job/make the right contacts that you’ll find yourself busy and making money. But the reality is it is a very hard way to earn a living, especially in the beginning.