Looks like you aren't in the US, so at least you aren't restricted to the US only sites like WPN and Chico. It's not always about the weaker players, it's also about the software and the so called "random" number generators.
In every room there will be good players and bad players. So I find it impossible to indicate a room that only has weak players or has more weak players.
There are no weak players anywhere! Everywhere, in normal, well-known poker rooms, there will be both weak and strong players. But there is an entry threshold in poker rooms. Play with a minimum entry threshold, as amateurs often gather there.
I didn't understand the question why look for weaker players? And what do you mean by weaker? In every poker room there are buy in limits micro medium and high. And that's how the strengths of the players are usually distributed, in the micro are mostly the weaker ones and in the medium the slightly better ones and the strong ones are mostly in the high. And yet you can find strong players in the micro as well as bad players in the high. But the probability of finding weaker players in the micro is pretty high. But then the question remains for me, weaker than what ? If you see yourself as a weak player then you will remain a weak player. And losing isn't always a sign of weakness, it's just a phase of bad luck