Stumped and frustrated

So I finally replaced a shitty 5 channel amp and eq. I had a taco tunes 5 channel amp and Recurve EQ. For reference I have a 2017 4Runner with image dynamics component set.

When I got this installed about 5 years ago I immediately had the following issues;
- static pop noise when turning car on
- ground noise out of right tweeter (would get louder when reving)
- bass non functional

I finally took it back in to another shop to get everything clear up. I had my doors deadened, installed pioneer GM-DX975 and Audio control lc7i pro.

Everything is great except I am still having ground noise. When I have the radio of you can hear a slight buzz/hiss still.

The shop said this is typical as the speakers aren’t receiving a signal. I found this hard to believe but I wasn’t quite sure what to say as this is not my expertise. I thought it was a ground issue or maybe a gain but the installer didn’t agree.

I’m happy with everything except this. The component set REALLY came alive with this new amp and it sounds great but want to get this last piece fixed. Any suggestions? I’m new to car audio as well.

Thanks