What are private servers like to a newcomer?

So classic wow is a lot more fun to me than retail but a lot of my friends wont play it cause of they sub. I was thinking we could play private server, something like wotlk because it seems overall the best in most regards. But there are a few things i was wondering.

Are private servers dead or well populated, are there active raid guild and pvp? Also are they the same as the wow of the time or are there major gameplay differences. Another thing ive heard is the servers are unstable and could be gone whenever. Also will i need a vpn?

When do Horde warriors replace their Axe?

I realize that there some good BoE weapons in the 40s, but there’s a trade-off there since you have to consider the value of the gold you are spending against how much better than WW axe that weapon would actually be. Obviously, this varies by economy of the server and your individual financial situation (whether it’s your first char on the server or you have a main to support you). How common is it for Ice Barbed Spear to be the item that finally gets rid of the WW axe?