Count Dooku is totally misunderstood. He saw the problems coming earlier than most people wanted to admit.
He got tired of watching the Jedi do the bidding of the corrupt Senate while the Republic just kept rotting, so he left.
A lot of the systems that joined him actually wanted out on their own. They had real complaints about how the Republic was treating them and he gave them a place to go. Using droids instead of actual people also made sense if you were trying to avoid turning the whole thing into a meat grinder the way the clones ended up doing.
The part that gets overlooked in my opinion is how much Palpatine was pulling the strings the whole time. Dooku thought he was working toward something better but he was really just being used. The war and everything that came with it wore him down until he wasnโt really the same person who left the Order.
In the end people only remember the โbad guyโ version of him, which I feels like misses a lot of what actually happened.