DSLR is a great place to start.
I started with canon XSi/450d and it’s a great camera. It has a good Signal to Noise ratio. And decent pixel size. It might not be very efficient as new dslrs, but it does the job for you. For astrophotography, you are not going to gain much by buying an expensive DSLRs.
Try buying an used camere if you know a reliable place to buy.
DSLRs are great to start with, but it can be frustrating when you are looking to image the nebulosity of a target.
My recommendation -
Buy used DSLR (save money)
Once your tracking is good enough and you are able to take long exposures, modify your dslr yourself.
Follow Gary Honis videos on youtube.
Try imaging with some good filters on ur dslr.
If the hobby still fascinates you, and when you are at a stage where you are imaging 180+ seconds sub exposures, consider buying dedicated astrocameras.
But it would be wise to spend money on buying a solid mount before considering an dedicated astrocamera.
Talking about your set up,
Here’s a tool that can be handy. Enter your telescope’s focal length and aperture to see what you can expect to see/image
Generally, for astrophotography, you’ll need a faster telescope, 90/1000, if I understand correctly is a F/11 telescope.
And at 1000 focal length, you are going to be lot closer to ur target.
While imaging at this focal length, small tracking mistakes can show star trails.
So your tracking needs to be very accurate for good results.
Also, aperture 90 means less light gathering. Less light gathering means, you’d need longer exposures to fill your camera sensors with photons.
But it is still possible to make a good image with this setup, but you need to work carefully on it.
The above explanation is by no means to discourage you from using the telescope for astrophotography. It is only to set right expectations to what you’d image using the telescope and the challenges you’ll encounter before making a good photo from it.
Happy to help!