Is your generator capable of 30 amps? Plugging more things into outlets on a generator doesn't produce more power.
Just use a 15/20 amp to 30TT adapter and limit your electrical use to your generator's capacity.
My 30amp rated contractor style LOUD generator has both 30TT and 30 amp 4 pole outlets (L14-30). I have it for home use with an L14-304 inlet plug panel.
I picked up a couple 2000watt inverter style QUIET generators, different brands, that I intend to link in parallel to get the 30 amps I need to run the TT power sucker gear

No AirCon or electric heating elements, & I can run just one 2000 watt generator.
Ballparking, you need about 3500 watts to get 30 amps.