I terminate wire directly to the amps. It will be the one bundle you dont have a disconnect for but its also the the one device you wont have to touch in 10 years.

I have done a few clean up projects where the existing speaker cable wont reach the new amp location. For this scenario i put a can in the wall and bring the existing speaker cable into it...then i use dinrail or terminal blocks...i even used wagos once...to splice to the "whip" coming off the rack.