Why is your "ultimate plan" to get an EQ mount. The EQ6 is a nice well proven mount.
I have been into Astronomy since I as 14, I am now 60, my personal friend was Patrick Moore and I spent many a week at farthings with his scopes and mine, in fact it was Patrick and I who did the reviews you see on OVL (and Skywatcher sales sites), so I am no beginner.
I say this because years back I made the mistake of thinking that EQ was the standard.
I hate EQ mounts, they look great in the shop but if you have to take them out and in again every time they are the worst thing to set up in the dark and cold and after an evening a pain to put away.
OK, of imaging long exposure they are needed but remember AltAz mounts can also be used for imaging.
Last year I retired at 60 and bought three scopes NO EQ, see images.
The one I use all the time takes NO setting up, a 120mm Refractor on AltAz mount, for imaging I use my Celestron Evolution AltAz, and for solar a 72mm ED on Gitzo tripod, I will be adding to this Ha scope next month an AltAz Skywatcher SolarQuest mount.
No one can say "buy this or that" only offer personal experience, seriously look at AltAz mounts such as
https://www.harrisontelescopes.co.uk...t.html#SID=568
Finally I would consider that most astro photography is done NOT with a reflecting scope, and as for cheaper new or used, the mount will be flimsy and balancing a DSLR on an already flimsy mount won't help
You can image on an AltAz
https://www.youtube.com/watch?v=uMXDHYCvnXw