I think this is a good scale.
Managing the relationship between interior temperature and outside sear (without burning) is a skill worth mastering first. Like you say, burgers, steaks, and other flat cuts are easier than irregular shapes.
Another skill to improve on is smoke management. Controlling both the temperature and the quality of smoke with fuel, heat, airflow is a balance: choking off burning wood to keep the temperature from rising too high tends to produce bad-tasting smoke, and giving enough oxygen for that thin blue smoke you want can sometimes cause the vessel to get a bit too hot.
Then, being able to control all of those things (internal temp, external temp, smoke quality) over a long enough period of time to cook tougher cuts is an increase in skill/difficulty. Smoking chicken might take an hour, while smoking ribs might take 3 hours, and smoking brisket might take 12+ hours. Some cooler cooks, like cold smoked salmon, can be challenging, too. Getting a feel for adding fuel to a cook and how to do that while maintaining the same steady stream of high quality smoke of the right temperature requires some experience.
Which also isn’t to say that there isn’t some room for a high level of skill on short cooks. Working with embers and wood and flame to make short cooks over high heat can be challenging, too. Smoked or wood fired vegetables are especially interesting, as some introduce moisture control as an element, over time frames short enough to precise timing starts to matter, too.
I don’t really bother with the middle of the restaurant industry (and it’s not just me, as chains like Chili’s and Applebee’s have complained about the trends hollowing out the middle). It’s just not enough of an improvement over fast food or fast casual to be worth the higher cost, slower service, etc.
If I’m hungry and don’t want to cook/clean, I’ll grab fast food.
If I want to sit down at a full service restaurant, it’ll probably be an expensive trendy place with recognition from James Beard or Michelin.