Hi all and welcome!
I am assuming that your devices have been shipped after june 2022 (if not please read wiki link above)
Pinephone Pro comes with kind of outdated Manjaro Plasma preinstalled.
As we speak it is known that there are issues with updating that particular preinstalled version of Manjaro Plasma - maybe these issues were not known when your Pinephone Pros were manufactured. I don't know but do not worry there is solution.
You have really cool device with you and the coolest part is that you can install whatever OS you want to it.
Don't be afraid it is designed like this - it is really really really hard to brick this device.
I suggest you to read this:
https://wiki.pine64.org/wiki/PinePhone_Pro
TLDR and just want quick fix?
1. Open your computer and Download latest postmarketOS Phosh stable installer image from here:
https://images.postmarketos.org/bpo/v22....0514-0505/
2. Boot your Pinephone Pro and press volume up same time - it will vibrate and boot to black screen and blue led is constantly on.
3. Plug your PPP to your computer with USB cord
4. Flash the postmarketOS Phosh stable installer image you downloaded to your PPP using for example Gnome Disks
5. After flash boot your PPP and follow the installer instructions
6. Enjoy working PPP