That backplate looks like it’s press-fitted into the housing (maybe screwed in) - I would get a light and look through the motors windings to see how it’s attached/fastened to it and if it’s press fit, see if you can put a metal rod through the winding and use a bench vise to press that back plate off, then you’d have access to the connection points for the plug wires.

Yw. As an experienced DIY’er number one rule for electricity is don’t mess with it if you’re not 100%

Yeah I had to re-read it three times.

What?

Call an electrician.