Doesn't a LF inverter with monster transformer like my Magnum 3000 typically have greater surge capability than a HF design? Mine could start my Coleman 15k BTU ac with 70 LRA most of the time without any help although it did complain, now with a soft start no problem.
Magnum doesn't seem lacking in technology, doing full load support and fully programmable charging for all types of batteries. It has a peak efficiency of 90% (The 24v version is at 94%).
I am currently monitoring it over wifi using some software I wrote to decode its rs485 protocol, it updates at 10hz on the bus it shares along with the battery monitor that updates at 2-3hz with battery voltage at 2 decimals places and shunt current.
Here is a great video of repairing a non hybrid one that gives you an ideas of its internals:
https://www.youtube.com/watch?v=m-1OSFPHi04What do you think primitive design?