Nah it's not normal to give out your personal phone number to people you play with. Discord is what most if not all people use. Even people I played with for years never had my personal phone number
Idk where your from but where I am, the natural progression of friendships is yk at first games, then discord. Then, when your like friends, close but not rlly close, your friends on instagram since its not really that personal, at least for me. So you dont risk private info apart from your face. And then after that is you become friends on fb. This is only true for friends ive met who is also from my country though. But usually its always discord-> insta
It's depend on the flow of your friendship and where you live. My country is relatively safe. Probably that's why some of guilds for my country only use Whatsapp instead of Discord as guild group.
If you're playing together long and close enough ESPECIALLY in same country, it's actually makes sense. Moreover, both of them are men so usually they are not really cautious and doesn't have to think about sexual harrassment or anything like that.