Another theory is that a large holder switched to Monero, or simply makes usage of this internal function as a mixer. eXch is really attractive for an anonymous entity. No KYC and supports Tor. It reduces some risks of de-anonymization by just sending and receiving bitcoin via Tor Browser, than to use a less reviewed, more complicated software like Bisq. (And it might be cheaper as well)
Fee for monero remans around 5% on eXch.
Something is definitely happening with monero that is affecting all exchanges.
Last I saw is the official ann from Coinex centralized exchange that is now asking for ID verification for depositing and withdrawing privacy coins Xmr, Beam, XHV, Oxen, Dero, Arrr, Zeph and Zano.
You can still use this exchange without verification for all other coins except for monero and other privacy coins

Dear CoinEx users,
Based on CoinEx's AML policy, from now on, ID Verification must be completed before depositing or withdrawing Privacy Coins. The specific arrangements are as follows:
Privacy Coins
BEAM, XHV, OXEN, DERO, ARRR, XMR, ZEPH, ZANO
Attention
1. In order to use the deposit and withdrawal services normally, users holding the above Privacy Coins are requested to complete ID Verification as soon as possible.
2. The deposit request of Privacy Coins will not be credited instantly without ID verification. Once verified, the deposit will be automatically credited.
Risk Reminder
Crypto products are innovative investment products with large price fluctuations as well as high investment risks. Therefore, please evaluate and invest wisely based on your risk tolerance and financial resources.
CoinEx reserves the right of final interpretation of this announcement.
CoinEx Team
Jan 22, 2024
https://announcement.coinex.com/hc/en-us/articles/22884451766804-CoinEx-Has-Required-Mandatory-ID-Verification-for-Deposits-and-Withdrawals-of-Privacy-Coins