Pinephone: Cheap. The device isn't very powerful. With people coming from an Apple device, that's a problem.
Fairphone 3: Fair. The hardware isn't very powerful either, and the device is more expensive, but the product is better for the people who assembled it and the environment.
Librem 5: Open. Even more expensive than Fairphone, but the hardware features killswitches, and there's no binary blobs. Lacks the fair advantages Fairphone has.
Each of these can run a myriad of FOSS OSes from a deGoogled Android (ASOP-based fork) such as /e/ or Ubuntu or Debian/Arch/Ubuntu mobile versions or SFOS (Sailfish) community version (without Android emulation layer!), and each hardware and software has their pros/cons. I use a Fairphone 3 with stock firmware with a Pinephone as back-up phone (and have to use a Samsung flagship device for work). Previously I used a Fairphone 2 with LineageOS + microG (kind of like predecessor of /e/ before that took off).
PS: On the gaming side, I'm getting a Steam Deck. Its a bang for the buck compared to Aya Neo/Nintendo Switch/gaming smartphones). No, it isn't open hardware, but the device runs Linux and you get root on it, plus all the reviews (including Linus Tech Tips) are positive.