Why were you looking to upgrade? Is the current setup (which closely parallels my own) letting you down in some way?
The two options you outline do not seem to be a big improvement to me. Also noting that your busted laptop screen means you won’t end up with a freed up laptop.
I would see an advantage in a beefier GPU or processor as your principal aims. Neither of these do that particularly. The Radeon is twice the graphics card the NVIDIA is, but I’d be debating whether the shift was worth the money.
That again comes down to whether your setup isn’t working for you.
There’s the
Blackmagic eGPU to consider for perhaps $1200 or indeed those new iPad Pros for the same money. And you’d have a portable computer back...