This has to be investigated more but for now it looks more like "fee market manipulation" to me. For some reason there is an "artificial" injection of a large number of transactions (the first suspect is the Ordinals Attackers) into the mempool to manipulate the fee market and significantly increase the fee rate by creating this fake competition.

Luckily the attack is becoming very expensive so it can not continue for long but the attack itself will not stop as long as the exploit in the protocol exists and the fake market where they sell fake tokens under the codename Ordinals exists. That is creating an incentive to spam attack bitcoin.