From what I’ve gathered from my experience and various forum posts is that the higher you are on the rating scale, the less variable the matches feel.
High variance (both in individual players and match quality) has many causes, many of which I list at How Competitive Skill Rating Works (Season 12) → “Matchmaking” → “If the match-maker says most games are fair, then why are there so many stomps?”.
A large fraction of the controversial posts on this forum are what exactly MMR does and how it behaves. Maybe you are new here.
The thing is, is that you have somewhere between anecdote and nothing, and I have pages of data and analysis which contradicts your conclusions.
I also have two smurfs, but they just placed gold and didn’t have win streaks of significant length, so they won’t show the effect that you claim, even if it exists. That’s why I showed the streamer data, which contradicts your conclusions.