I too would vote for changing to a main-powered heater with an SSR.
I did that some time ago and downsized the +24 PSU to a 240 watt unit, which is overkill for the printer's remaining requirements aside from the bed heater.
The actual requirement for the printer (again aside from the bed heater) is probably on the order of 80-100 watts (even with a 60 watt hot end heater as I have).
The added bonus is very rapid heating of the print bed.
I can go from cold to printing ABS in less than 5 minutes for example.
FWIW, the PSU is one of the last things you want to skimp on.
Get a good quality one.
Mine has a MeanWell and it is robustly built.