Limited power in 2004 38 ft monoco sahara Safari

Read your post twice but I can't quite make sense out of it.
I start my generator all the time while plugged in with No problems.
I am going to read your post again. I am an electrical troubleshooter and would like to help.
My ACs have a two minute delay to kick in.

After reading again it appears you have lost 12 volts. Did your battery disconnect get activated?
Not sure if your thermostats are powered off your 120vac or your 12v supply.

have you checked the two smallish fuses on the inverter? They pop out and needed to be pushed in to reset them.

Check the reset for your converter and or inverter one of them may have tripped.

Also on my RV there are two circuit breakers mounted near the slideout controls, one of these also provides protection to the converter. The circuit breaker is the automotive type small black plastic about an 1 1/2 long with a micro switch to reset and two wire connections.

And one or more of your GFCI receptacles may have tripped and is affecting the entire circuit.

unplug shore power
turn off ALL breakers, all the way off, including the TWO breakers on the SIDE of your Generator

also check your INverter charger/converter devices
for circuit breakers and fuses mount on them

leave shore unplugged
try the generator first, check all circuits for power
yes you could have damaged the transfer switch, it might have burnt stuck contacts and not switching correctly

save that for last you will need ALL power off and disconnected before opening that and sticking your fingers in there

after you test the Generator, turn it off and then plug in shore power and test again

BTW this is why you should unplug shore power first

I'll say it again
an RV transfer switch is NOT the same as an Emergency power failure switch
generator power switch

ONE important fact is missing
the UTILITY COMPANY POWER FAILURE
in power fail situation, utility power has failed. before the generator starts
it is already dead no incoming power
loads have already been turned off, by the power failure
even if it is only seconds in the switch
NO hot loads are switched, no arcing of utility power on the contacts
no sticky contact causing a cross connection

ALWAYS ..ALWAYS..turn off loads, unplug shore power before starting the generator
the few minutes of lazy butt time saved are NOT worth the RISk

Thanks to all who posted.
Its Fixed
I turned everything off, all breakers including breaker on generator, invertor and ect. Turned battery bank off.
Slowly turned everything back on. Don't forget breaker on generator must be turned back on.
Everything worked except thermostat in hall which controls air conditioner and heat pump. I had no power to it. From there I tracked problem down to a 3 amp blown fuse in back air conditioner on roof. Cost me .75 cents for fuse.
I will be more careful from now on about turning generator on while shore line pluged in.
Thanks again to all who posted.

Our 2000 Monaco has a rocker switch on the dash to start the generator without going outside. This means that it is OK to start the generator without disconnecting from the electric. Doesn't yours have the same? Our converter automatically switches to the generator if running and then back to the electric when the generator is shut off. Maybe your auto portion of the converter isn't working correctly.