apt-key is still supported in Debian 11 and its derivatives like PureOS, but it won’t be supported in the next version of Debian.
You can use something like this command, if the key is ASCII-armored: wget -O- <https://example.com/key/repo-key.gpg> | gpg --dearmor | sudo tee /usr/share/keyrings/<myrepository>-archive-keyring.gpg
Then add something like this to your /etc/apt/sources.list file: deb [signed-by=/usr/share/keyrings/<myrepository>-archive-keyring.gpg] <https://repository.example.com/debian/ stable main>
Personally, I think that the new method is a cumbersome, so I am still using the apt-key method, because I don’t think the security risk is that great. I hope that they figure out something easier to use by the time of Debian 12.
I’m using chatty with tdlib-purple on pinephone running Manjaro Phosh, I’ve not seen any crashes as of now. That’s how I realized chatty can support Telegram.
There are 2 options available tdlib-purple-minimal and tdlib-purple. tdlib-purple depends on VoIP library and doesn’t build at all since VoIP is not yet ready for aarch64.
I’ve been trying to get tdlib-purple-minimal built however I’m not yet successful. Takes multiple hrs to failure and I couldn’t debug