I just cut through a 6x6 pressure treated beam with my Ryobi brushless circular saw. Didn’t even bother to upgrade to a diablo blade. And it worked great!
I made six more similar cuts. No problem.
If I was doing this every day, would I upgrade to Milwaukee? Probably. (More than likely buy a corded saw.) But for weekend home improvement projects, don’t doubt the power!
milwaukee stuff is really good. never used ryobi, though some folks I know prefer them