The puzzles system will pull ones that are generally +/- 400 of your current rating. I believe there's also some part of the algorithm that if you are getting them right will tend to give you more above your rating and if you get more wrong, they'll trend downward.
For me, I notice rating streaks are more indicative on how I feel mentally during a session and less to do with the actual puzzles.
I made a post here the other day about me lacking consistency, and I referenced the opponent algorithm giving me a bunch of easy opponents in a row, then a bunch of hard opponents in a row. The exact same thing happens in puzzles too, bunch of easy ones, then a bunch of solid puzzles to knock your elo back down.
I don't get why it works in chunks like this, its really bizarre. All it does is result in large elo fluctuations. This is exactly what will happen - yesterday I was getting close to hitting 600, today I am playing bad IMO, but all opponents are playing much stronger than yesterday. I am back down to 500 basically. But then tomorrow, I will have a bunch of easy ones again and smash through 600 in a breeze.
Its a very bad algo they use here and it makes for bad match ups. Tomorrow for instance I will be at 500, then play someone at 560 and beat them relatively easy. They will be scratching their head as to why. Because of how this elo works..... If it just matched people consistently, you wouldn't get wild swings like this and the games would be more balanced.
Its annoying from a playing point of view, I wanted to play some games today, and have, but I know I am just getting harder opponents. It does not make it fun. I might just start abusing it. Soon as I realise its giving me a bunch of hard opponents I will just log out and come back later or go lychess or something, then play again when its the easy ones.
Other people have surely noticed this, its such an obvious flaw in their algorithm and the same over and over again. Its extremely noticeable in puzzles, they go from so easy to near impossible and when they go near impossible, just stop playing.
Some of you will say conspiracy or something. Its not, its just how they badly programmed the algo. Take the puzzles for example, I do 20 in a row, every single one is so obvious to me, that its honestly super easy, then they change, and the next 10 every single one I am looking at it scratching my head, like wtf is this??
Please update the algo to stop these wild predictable swings, it just makes a really bad experienced and ultimately, people will use this place less.