Supposedly, he sells out of his phones but I haven't seen any review or unboxing videos for the Brax 3. I know that you can ask for iodeOS or Ubuntu touch.
I heard that he was a scammer or pseudo privacy expert from other comments. I wouldn't recommend that phone. If you care about the privacy or security of your device, use DivestOS with a supported Pixel/OnePlus, or GrapheneOS with a Pixel. Only buy the phone new if you are super paranoid of some zero-day vulnerability being used on you. I recommend swappa.com because they have quality control, returns, and good prices for used devices (you can even get mint quality devices).
iodeOS has been behind on security updates often (still better security against unsophisticated attacks than Ubuntu but not a good ROM): https://divestos.org/pages/patch_history
I learned about Swappa years ago and exclusively use them for buying and selling all my smartphones. I have no idea why they aren't more popular, except for the fact that repair shop resellers use it too, but they are pretty easy to avoid.