Slow 4G connection only, but only sometimes -- SOLVED

I have posted in many threads and I have done tons of testing.

At this point I have 2 places in my home that the can can go.

Here are some issues I have discovered.

I have 2 4G towers one is .5 miles on the west the other is 2 miles direct line of site no obstruction to the south.

I have only one 5G tower in range 1.5 miles to the north west.

If I locate the can on the west side it gets the 4G tower and the 5G tower ok signal not great but ok. I get speeds day not so great in the 50's many times much less. At night as in 2am good speeds over 100. So seems these towers are overloaded in the day and I would think so there are several hundred homes there.

If I locate the can in the south window it gets great signal from the 4G tower as it is viewable with just the eye. But it gets not so good 5G signal since that is around to the NW. Speeds are like 1-2 as the can wants to use the 5G that is really bad signal.

Now testing with a phone. Phone on 4G on the west window same issue as the can slow 50ish. Same with 5G as these towers I know have many ppl on them.

Take the phone to the south window where it gets that 2 mile away tower that has no homes around it and the phone easily gets 150+ down.

I don't understand why the can does not get the same speed in the south window. Seems the can if it has a 5G signal even if crap it wants to use it even though the 4G signal it has would yield way better speed.

Thoughts?