What is the max size chainring your frame will take? Some mtb frames that are 1xspeed are limited to chainring size like a 34t.
A smaller chainring sacrifices top speed but better climbing abilities and less stress on the motor on steep prolonged climbs.
Off the shelf e-mtbs tend to have a small chainring like a 32t, so it’s not like it would be unusual to fit a smaller chainring.
As a budget option, why not keep your 32t? You may need a converter for the kit though.
If you want more top speed then you can always fit a larger chainring/ cassette at a later date. Obviously there is the legal side of max speed and power for electric assistance but I’ll try and leave that can of worms closed…