Originally posted by N-14:

just want to buy Valheim because of the hype and the sudden increase of player base.

Those are THE worst two reasons to buy this game, or any game for that matter.

Ignore hype.
1. What might seem popular to others doesn't mean it's a match for you.

Originally posted by Suzaku:

do your due diligence. Check out gameplay, maybe watch some streams, ask questions. Know what you're buying before you put your money down.

This is good advice. Do your own research, especially for any Early Access game. Watch gameplay and examine the patch history.
https://valheim.fandom.com/wiki/Version_History

2. Ignore player base numbers.
"Player base" is meaningless. You're either going to play this solo or you're going to play this co-op with someone you know. You are not going to want to play with strangers.
The reason for the recent increase is that the latest update is something players have been waiting a year and 10 months for. The current 30% discount doesn't hurt either.

As an Early Access title, you have two options:
Buy this incomplete game and help the dev's by providing feedback until they're done. Be aware that may take months or even years.
Or, follow it and wait until they finish developing the game.