I assume your 110-220V transformer is an autotransformer as it uses less copper and you don't need isolation. Autotransformers do exist with the ability to select the taps on the input and/or output, changing the ratio slightly, and you can also get variable transformers (example manufacturer) that would allow you to fine-tune.
There may even be a service that can rewind your existing transformer for lower output voltage. The difficulty here is that they'd need to remove about 1/6 of the turns to get from 265V to 220V, and that means knowing how many turns there are to start with.
It would be possible experimentally to measure the voltage on the output, remove several turns, reconnect, remeasure, and calculate the number of turns still to be removed. I'd consider doing it myself on little transformers, maybe even for mains use, but I have experience of mains work. This wouldn't be a job for an electrician but again would be something a transformer/motor/coil winding company could do - if you can find one that still exists.
A mains-input inverter with variable output voltage might be cheaper; I've only used them in 3-phase when we also needed to change the frequency. This Mitsubishi is getting close but not quite right as the output current is too low, you're also right on the edge of the input envelope on this and many other models, as 200-240V ± 10% (or +10% -15%) is common, giving max 264V.
One thing that won't work is adding a series resistance. The load is too variable for that. If you calculate what you'd need at maximum current with the element on, you'll have too much when it's just driving the logic parts or even the motor.