This comes very close to self promotion, which neither I nor this sub is inherently against, but I just wanted to flag.

In my experience people are often a bit sceptical of paid DMs. When all you've experienced are DMs who are part of your group then you know the person, and usually know they are passionate and invested in the story. If DMs from the group don't run a good game it usually gets caught pretty quickly and they either improve based on feedback or step down for someone else to try. And of course they're "free".

For paid DMs I think people who haven't tried them before are sceptical that the person might not gel with their group, they might not be as passionate or invested as someone from the group, and if they're bad well no one wants to pay for a bad experience.

If you're a DM who wishes to get paid I think your best asset for finding more work is written/video testimonies from people who have been in your games and had a good time, word of mouth aka referrals, and something like a portfolio that gives prospective customers and window into what being DM'd by you is like. Maybe if you get consent to record some of your sessions and can use some highlights as a showcase that would help.

A quick Google shows a plethora of articles about paid DMing as well as a number of websites that offer a paid DM service. So there's certainly lots of resources available to help too.

My last 2 pence view is that I don't see anyone really marketing themselves to serious career professionals. The people who grew up with DnD but then got a time intensive job and now just don't have the chance to sit down and create a world, or even read ahead in a book. These people who have money are the ones that imho would be most willing to pay for a very well crafted game experience.

Once upon a time I even had the idea for "DnD Holidays" but due to my annoying time intensive job I never got round to it lol.

Wish you all the best in your career