Greetings,
The information you provided is helpful, thank you.
At this point I don't know that I would recommend investing in DSLRs.
I think mirrorless is the direction you want to move in. There are some considerations. Is the 17-50 the only lens you own? I owned the 17-70 which I absolutely loved. It came out shortly after the 17-50. Given the age of the 17-50 I'm not sure how well it might work with a modern mirrorless body. It's firmware cannot be updated unless you send it back to Sigma and I don't know if firmware is even available for it.
You can only use the Sigma Dock on Global Vision lenses (Contemporary, Art or Sport).
This is the list of compatible mirrorless bodys for the 17-50 from Sigma's website
The 90D is supported, but this relagates you to staying with DSLR's. Not a bad thing, but if you are looking to make a single step upgrade. The 90D is a great camera.
If you are looking for a major upgrade, then a mirrorless body is the way you'll want to go. Here's a side by side.
Canon R7 vs Canon 90D Detailed Comparison (cameradecision.com)
Very close, until you consider IBIS, more advanced focusing system (Animal, Vehicle, Eye tracking), more AF points, better ISO, 2 card slots, etc. and you get these things for $200 more. 2 yr old body vs. 5 yr old body. The R7 is lighter too, and also weather sealed like the 90D.
Don't make a decision because its what I might do. Go look at the 2 together.
If you want to stretch your dollar, consider Canon Refurbished.
Canon Refurbished Cameras & Accessories | Canon U.S.A, Inc.
R10 - $783
R7 - $1119
90D is there too.
The R7 with 18-150mm Refurb is out of stock, so mix and match. Refurbished body, new lens.
You have some options. Then sell the T6 and Sigma and use that cash to buy a few memory cards and extra battery.
