We asked this question previously in the Uborts forum:

https://forums.ubports.com/topic/10004/are-there-any-privacy-issues-if-we-choose-a-phone-from-google-like-the-google-pixel-3a-3a-xl/2?_=1720119547851

Privacy expert Rob Braxman entiteled the Nexus 5 with Ubuntu Touch as the safest phone wich is available to anyone in the year 2020:

The Pinephone keyboard is gone, will we become happy with the Rii mini 4?

We miss a statement from Rob Braxman about the safety of the Google Pixel 3a with Ubuntu Touch. But the answers given in the Ubports forum are also very helpful.

Issues it has for us personally of the Google Pixel 3 with Ubuntu Touch:

• it can’t write as freely to the external SD card as the Pinepeone.
• It has no hard wired keyboard as the Pinephone once had.