The question I asked myself almost three years ago, what new laptop to get, finally got resolved a few weeks ago. The old Thinkpad X230 still has not broken down, but I need to compile things at work more often nowadays, so a more modern machine made sense.
Thus, after some more agonizing, I bought a Dell Latitude 5401 with an Intel i7-9850H, 32Gb of RAM and a fast SSD. The not-tiny formfactor suits me well and I like the larger screen. Skipping the Microsoft-tax by ordering it with Ubuntu pre-installed is a plus. So far it does its job well enough and I do not regret the choice.