Is placements system broken?

I’m used to get four gold medals or even five medals at a rate of 10k in everything. But when I finished placements I saw that my rank is gold … but I managed to get in another account to masters-gm… But I think the reason why I’m in gold is that I was playing as a flex main
Is this the reason or that the system is broken ??

Placements are determined by previous rank, followed by win loss record, followed by performance (for diamond and below).

New accounts start their first game at about 2350, and go from there.

More detail at How Competitive Skill Rating Works (Season 15).