dtc

Confesso que não conheço os sites dessas marcas, já há muito tempo que não pego num Samsung. Se forem referenciados por users com boa reputação no XDA deve ser minimamente confiável.

És capaz de encontrar uns telemóveis em segunda mão baratos, verifica que têm a compatibilidade que queres. Penso que o OnePlus 6, por exemplo, funciona bem com o postmarketOS.

Para voltar ao firmware inicial tens de ter o ficheiro que o contém. Para os Samsungs isso deve ser fácil de encontrar, e depois podes usar o Odin para fazer flash (não é um processo muito complicado que me lembre). Para o Alcatel, tenho as minhas dúvidas.

Quanto a dual boot, esquece isso, se o suporte para o resto das coisas já é o que é, não deve existir nada que te deixe fazer dual boot. Infelizmente os telemóveis não funcionam como computadores :(

Se usas um destes devices regularmente, então talvez seja melhor não tentares brincar com ele, há sempre o risco de dares brick permanentemente neste processo, especialmente se for a primeira vez e estiveres a usar ROMs não muito oficiais.

Para Linux, recomendo PostmarketOS, embora penso que o suporte para esses dispositivos não seja muito bom (ver as páginas abaixo):
https://wiki.postmarketos.org/wiki/Samsung_Galaxy_S_II_(samsung-i9100g) (não parece ser exatamente o mesmo modelo)
https://wiki.postmarketos.org/wiki/Samsung_Galaxy_Tab_A_2016_(SM-T580)
Páginas para o SM-T280 e 4047D não parecem existir

Quanto a LineageOS, o processo é geralmente simples, embora seja provável que a maioria do que encontres esteja desatualizado. Além da wiki deles, recomendo procurares no XDA Forums, sempre tens mais algumas opções de ROMs.

Se tiveres mais alguma dúvida diz!

While the disposable cards might not always work, you can always create a regular virtual card and delete/freeze it afterwards. Not sure if there are any limits tho

Not really the same thing, but Revolut has disposable virtual cards that you can use (but it's a full-fledged bank).

Some apps like MBWay in Portugal also allow you to create these virtual cards, but it requires a Portuguese bank account.

I've had this "problem" before, and I did not want to use the full Messenger app for privacy reasons as well. I had installed Messenger Lite, but it was discontinued a few weeks ago. I now have Facebook Lite, which also has Messenger, and you get notifications as well. It's not perfect, but don't give it too many permissions and you should be mostly fine. Using it in the browser is absolutely terrible, and you would not get push notifications.

That's great to hear! There are still some apps on my phone that aren't taking advantage of it then -- or perhaps it has something to do with my custom ROM.

I'm unsure if this is still the case in the latest Android versions, but the terrible camera APIs in 3rd party apps/social media apps is still a big reason why my non-techy friends switched to an iPhone. Even if the quality of pictures using the stock camera app is good, if the photos that come out while using Instagram or Snapchat or whatever kids are using these days are low-quality, they'll consider moving to an iPhone. Again, I'm unsure if the APIs already exist or if it's just app developers that are not using them. Either way, there needs to be a push in this direction.

That's nice to know, I'll definitely deploy it soon then! I'm currently using NextCloud Photos, but face detection is so bad it can't even tell male and female faces apart properly.

Thank you!

I've been wanting to switch to PhotoPrism for a while. Is face/object detection any good, compared to Google Photos? Do you need powerful specs, or can a low-spec machine handle it?

I self-host my own mail server. I don't send many emails, but they seem to be arriving correctly whenever I do at the moment, but it wasn't always like this. I've properly setup SPF, DKIM and DMARC, which helps a lot, but my IP address was blacklisted on some servers from a previous owner I guess. I have a VPS from OVH. I had to manually fill out some forms to get Microsoft Outlook to accept emails from my server. Despite that, it has been working flawlessly. I have my own domain since 2017, and I'd say the age of the domain is also important.