A bit off topic but relevant, I once had a 3 phase 600 volt 60HZ electric blower unit, came from a submarine the tag on the motor said it was rebuilt and gave a date and military number etc. I ran it on 415 volt 50HZ as I thought at the time that would be OK. big mistake after about half an hour run it was smoking hot and within the hour the windings had burnt out, and this was military grade equipment. I learnt then that it is a NO NO to run 60 HZ at 50 HZ unless it states on the label that it is 50/60HZ.
Motors & transformers are very different---We had troubles with blower motors from the USA,but never with transformers.
I reiterate,if it is a quality transformer,it is very unlikely to give any problems,even if it does not specifically say 50/60 Hz.
Western Australia had
40Hz for many years,but transformers for 50 Hz didn't blow up!
In any case,the equipment the OP is talking about is not going to be used 24/7.
All that can happen with a transformer supply is that the transformer will become slightly warmer--if it becomes noticeably hot,you can always try something else,but going with extremely complex methods to get around a probably non-existent problem strikes me as a waste of time & money.
Did US military installations in 50Hz countries have huge rotary inverters (or lots of little inverters) to give 110V 60Hz in the past?
I don't think so!