Starting Point - Descent Subs

I'm having trouble getting descent subs. I'm new so I haven't had a full year of weather and seeing conditions to work with. I know there are a lot of variables and I'm working through those as I go. But I'm wondering if anybody has any thoughts.

My subs are incredibly noisy and very difficult to work with.

Here's what I'm doing -

I'm in a Bortle 8 area.

Canon T7 ( I have a cooled ASI1600MM on the way, but still on backorder)

Optolong L-extreme dual band filter

tracking and guiding are spot on.

I shoot anywhere from sets of 300 sec to 600 sec subs. I'm only able to get 20 or so. Low number of lights could be part of my problem.

20 Dark

20 Flat

20 Bias

Seeing and Transparency might be another huge factor. Temperatures in the 100's during the day, so the Canon gets pretty hot. I'm thinking a great deal of the noise is just heat.

I also live in California near where all the fires are burning. While it isn't too bad where I am, I'm sure there is some residual smoke in the air.

I'm attaching one of the light subs as a reference.

Any thoughts?

Thanks in advance,

Jim