Technically, veganism requires only what is possible and practicable. If you genuinely needed to eat a hundred grams of chicken each week for unavoidable health reasons, you’d still be vegan, if you abstained from any other animal consumption.
It also doesn’t have to work for everyone, just for most people. If you 20% of people were vegan, we’d end up with a snowball effect that made the world a better place.
I have never had a good experience with a Debian server. Every single time I had to add unstable or third party repos to get anything remotely current to run. What’s the point if you have to add unstable shit anyway?