Honestly, self-host a mumble for your friends. Faster, better and without the ads.
Would be nice if people started doing things in the open, like a Discourse indeed.
Consider Mumble over TS. 
Not like you will notice a difference on the end user experience but it has the edge of being FOSS.
Try to do the hard part yourself then show them how easy it is to be elsewhere and they should experience less friction as a whole.
Yeah. That’s a claim, at best.
Just let it casually upload your face and full photo library for 10min, then remove the permission?
Defeats the whole purpose of permission. Also, once exfiltrated from your phone, there is nothing to really be worried about. It takes mere seconds/minutes to upload the integrity of your mobile phone’s photo library to a CDN like AWS S3 if connected to the WiFi. Especially because this can be done in the background.
Guess it’s really time to move away from Discord. 
Was never a good platform to begin with tbh, not a huge loss.