I got the Xiaomi 9T Pro (variant of the K20 Pro) when it was released, it's one of the very few phones that fulfill my criteria for a phone that would last a long time
* Repairable (modular design, pull-tabs for battery)
* Good build quality (JerryRigEverything approved)
* Rootable
* Stable software, with long term vendor software updates
* Active community for ROMs (if the vendor stops supporting the phone)
* 3.5mm jack (with an excellent DAC)
* Relatively compact
* Flat screen, no notch/holepunch. Curved screens are more fragile and are more expensive to replace.
* Good battery life
* Spare parts available (e.g. main camera for $15 shipped)
* Cheap
* Decent processor, RAM and storage
There are some downsides, so not for everyone:
* Comes with bloatware, some of it can only be disabled with root
* Rooting is a pain
* Spare parts in China, so might take a while to arrive
* Launcher is not great, but can be easily replaced
* Camera is not best in class