Just like what happened to used veggie oil...

The motors are AC and it'll have a variable frequency drive (fancy inverter that changes frequency to drive the motor at the desired speed). Also provides the regenerative braking by running at a lower speed than the motor.

DC motor EVs are not really a thing any more, outside of hobby conversions.

Low power VFDs are dirt cheap these days, but a 65kW one would run a few thousand. A brand name industrial spec one in that power range would cost $5-10k USD.

Charging from home is AC, and IDK maybe it also contains the charging control for DC?
Anyways the inverter alone is generally upwards of 1000 Euro.

the motor is ac

True, but they could still have a tariff on ALL cars. Or only Chinese just to make USA happy.
Here in Denmark where we also don't make cars, we used to have a very high tax on cars, officially to limit pollution, but also because the state was low on money.
This dated back to post WW2 where for years for instance color film was illegal to import, because the country lacked the wealth to import luxury items.
Even when in the EEC later EU we still had/have high taxes on cars, but they were not called import taxes, they were added at registration, so it was called a registration tax, that however was obviously a workaround, and EEC/EU allow it.
Taxes are now way lower on cars, because to stimulate transition to electric, they have way lower registration tax, and the sales of BEV cars is 90% now.

Not exactly, GM and Ford in Australia and Canada lived off billions in corporate welfare. When Australia refused to keep paying, they left.

Canada really needs to rethink it's relationship with Detroit. Ottawa likes the export value numbers, but we certainly subsidize this industry that only makes thirsty trucks.