Update: Purism support said it might be an hardware problem and will replace it since it’s under warranty. In one day they sent me the “return label”, so I just had to put the phone back in its shipping box along with its accessories, went to the postal office with the return label and that’s it (I’m in Europe and the phone is being sent to Germany. Since it’s a replacement, I won’t have to pay for customs again). Purism support is great, now let’s hope the new/fixed phone is shipped fast.
To quickly delete personal data, I removed .config, .cache, Music/Documents/Downloads, .local/share and few others, plus I removed some of the installed app.
Side note: I’m back to the pinephone, which feels slower but hey, at least I didn’t erase data on it.