You have a Crossbow Expert. You have had a far easier time. I know if we had archers, the dragon wouldn't last long. It has been spending the fly spell to engage that has been screwing us up badly.
Foresight is awesome. I sure do want to try Shapechange. That spell looks fun. I imagine they'll errata that before too long. DMs will not be happy having everything beat with that spell.
I'm still shocked they made Forcecage and Wall of Force so powerful. No save locking a creature down is very powerful.
I puzzled over why Forcecage wasn't concentration for a while, it's very powerful.
However now after seeing it in play a few times, yes it can trivialize a lot of encounters, but it's also a 7th level slot. The Wizard in my group will only have one of those per day for quite some time, so it does consume a lot of resources in that sense.
My current group that I DM for is about to come across a CR20 Shadow Dragon without Crossbow Expert Cheese (Paladin instead of a Fighter), and of course I made it the spell casting variant (misty step). Let's see how they do.
