I'm eyeing my first flip, I'll be using sweat equity for as much as possible because of financial constraints that I project for the first few properties. I did a lot of work on my single family home previously, which does not make me an expert, or talented, or time efficient but it has provided me enough experience to know that if cash is tight I'm capable of certain work such as landscaping, painting, drywalling, patching walls, adding baseboards and trim (it's satisfying to finally use geometry). I've even done a roof before and would consider doing it on a single story home or garage. Long term, I have no plans to do reno work but I do believe the more hands on I am in the early flips the easier it'll be for me to spot a good contractor from a bad contractor.
In your case I think you should do one or two properties but keep a close eye on your time vs how long a contractor would take. Also, there is no reason you can't have a satisfying side project ongoing while you have most of your projects being run by a GC if the manual labor makes you happy. Gotta be happy otherwise why are we all doing this?