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