I was able to promote my Volla X23 to my daily driver phone a few days ago and I am loving it. The battery life is fantastic. It is off the charger for usually around sixteen hours each day and I still have around 70% left most of the time. I use it for Matrix messaging; web browsing; Minds; and email.
Volla OS itself is fine and very similar to other Degoogled versions of Android. If you've used /e/; DivestOS; Lineage; or others you should be at home.
The phone itself is a brick. It was made for durability and I have no doubt it will meet that goal. Even without a case on it is probably twice as thick as most other phones and the extra size wasn't put to waste. Not everyone will like this but I do. If you don't I would check out the Volla 22 as it was meant more for aesthetics and specs rather than durability.
My only complaints so far would be that the battery covers up the sim card slot so any time I were to want to remove it I have to remove the battery. Also while currently you can use the Ubuntu Touch installer to install either Volla OS or Ubuntu Touch that wasn't the case until very recently. I think this should have been available day one.
The folks at Volla have been great to deal with as well when I have had questions. I paid about $900 CAD for the X23; a case; a spare battery and government import fees/taxes. Worth every penny so far. I got a phone which gives me options for operating systems; a removable battery; decent specs; and fantastic build quality.
If you're in Europe you can purchase the X23 from the Volla Store:
https://volla.online/de/shop/volla-phone-x23/If you're outside Europe then you'll want to purchase from the Indiegogo campaign Volla has:
https://www.indiegogo.com/projects/volla-phone-22-the-beauty-of-freedom#/