That is about what I spent for my new Mini with 6-core i7, 64gb RAM and 2tb SSD, plus a 32" BenQ screen. I also considered an iMac but wanted a bigger and more adjustable screen, plus I was concerned about the same issue you are having... if something goes wrong with the computer and it's not worth fixing, you basically just throw away the expensive screen.
It is a lot of money and I agonized over it for awhile. Would have been cheaper to use my own RAM, but there are issues with that. I was also upgrading from a 2012 Mini and 2013 MacBook Air. IMO, 8 years is a ripe old age for a computer if you have anything more than casual needs...
But you should be fine with the external screens on the iMac in the meantime, I'd think.