Moving to B&II for a better fit.
The camera to buy today *for astrophotography* is the Nikon D5300 (or D5500/D5600). The reason is the low dark noise. The Canons (the T6i is a decent choice) are noisier. Note that you *only need the camera body* no matter what you buy.
The linked ED-80 scope on a Sirius mount is a very good budget choice for beginning astrophotography. Note that you will need a *field flattener* for the scope. I recommend the Hotech SCA 2". You will also need a guiding solution, likely a 50mm guidescope (Orion sells it) + ASI120MM-mini guide camera (multiple vendors, google it). Also I would recommend the excellent Backyard EOS/Nikon software for $50 to control the camera. Another item would be a Bahtinov mask for precise focusing. The whole shebang should be well under $2,500.
Don't get a larger refractor. It is *not* an advantage (the opposite of visual). The larger refractor will have a reduced field of view, will be heavier and longer and therefore harder to track with. An 80mm refractor will be useful to you no matter how expert you become.
However, if money reaches, I could well recommend a different refractor, such as the AT80EDT. It is F/6 rather than F/7.5 which cuts down the time you have to image, makes tracking easier and expands the FOV at a small cost of image scale, it has a better focuser and better rings. I would still recommend the same Sirius mount (or possibly the Atlas/EQ6R-Pro if you are young and strong--it's heavy).
Newtonians are much more of a pain. In addition to collimation you likely will need to replace focusers, and tracking will not be as good.