Last act I started Immortal 1 with a Dia/Immortal act rank. I was able to climb to Immortal 3 with a 60% win rate, but I was still facing many Diamonds in my games. Even at 150RR I would be with Diamonds. There was honestly no difference in the skill level in my games from when I climbed from Immortal 1 to Immortal 3, and it was disappointing because I wanted to face better players.

This Act, I started Immortal 1 but I am now with previous Act rank high Immortals. My first 5 games this Act have had much better players than any game I had last Act.

This makes me think that your previous Act rank largely determines the games you will be placed in the current Act. An Immortal 2 with an act rank of Diamond will be placed in lower elo lobbies than an Immortal 1 player with an act rank of Immortal 3.

I personally don’t think this is a good design because it just makes people hard-stuck in their rank. Last act I climbed 200RR from Immortal 1 to 3 and there was zero skill difference in my games.