Curious transactions on the blockchain right now

I'm just curious to know what the hell is going on right now. Since yesterday someone constantly adds huge transactions to the mempool that aggregate bitcoins from hundreds (up to 1000) almost identical UTXOs into one, not even using Segwit, just plain old legacy addresses... I was hoping to open some more Lightning channels for 1sat/vB, but the mempool is being filled by something that looks to me like a huge mixing operation...

https://mempool.space/tx/36d5eb08110aa6dd73d09a831f279b423a17a9be0d552cebac7dc7003c6e82c5

There are also these transactions that aggregate 300-500 of 2 of 3 UTXOs with absolutely identical, very small, balance.

https://mempool.space/tx/9f684469c85350d35e6c4641f4960aa23c1004b1fc1a999761bd57af7308bfb8

The addresses are generally very old... They were in use since the beginning of 2018... Since then, each of the addresses has been used in hundreds or even thousands of many-in-many-out transactions...

And just like yesterday the rate at which new transactions are added to the mempool seems to be artificially held at a "balanced" 1600vB/s... You can see it on the mempool graph as regular staircase-like growth of 1sat/vB bucket... It started at the same time as yesterday too - 9AM UTC…