I’m someone who doesn’t need flash features, just speed, reliability and the ability to be kept up to date. My suggestions would be Xiaomi, One Plus or Pixel phones for the sole purpose of being able to keep them up to date with custom ROMs and reducing the dependency on Google - you need to make sure the device has good community support, however.
If you pick the right device, you might get some Sailfish and UBport support too. The other option is a phone that has a potential decent Sailfish port in current development - I got sick of how slow my Xperia 10 was, I left Sailfish, only to return after buying a Sony XZ2 and having way better performance with Waydroid running in the background. Alternatively, spend the money on several second hand phones to allow you to dabble in multiple operating systems like me, haha.