First, all food/beverage hospitality workers in California.[1] Huge COVID transient, followed by recovery to almost the pre-COVID level. But no further increases.
Full-service restaurants had a similar transient, but never came back to pre-COVID levels. Employment peaked in mid-2023, and has declined since. Full-service restaurants didn't get the $20 fast food minimum wage. But workers there may have tip income. California does not have a lower "tipped minimum wage", and all tips go to workers.
What FRED calls "limited service restaurants and other eating places" shows about the same curve as full-service restaurants.[3] This includes both the fast food chains and the fast-casual restaurants. If you have to order at a counter, it's "limited service", even if they bring out the food later.
So, the part of the restaurant industry that wasn't affected by the increase shows about the same trend as the part that was. Basically, post-COVID, onsite eating never fully came back. Food delivery became a much bigger part of the industry.)
Those stats are regardless of business size. California's minimum wage law for "fast food" applies only to businesses with at least 60 locations. But it also includes such things as 7-11 stores that sell hot dogs and pizzas heated up on site. So, not an exact match to the FRED categories.
Overall, the COVID transient and its aftermath is bigger than all other visible effects.
[1] https://fred.stlouisfed.org/series/SMU06000007072200001SA
[2] https://fred.stlouisfed.org/series/SMU06000007072251101A
[3] https://fred.stlouisfed.org/series/SMU06000007072259001SA