"Crypto Exchanges are more likely to be compromised, so please put some of your assignments into a wallet right now.
Exchanges can be compromised, hacked, unable to do compensation for users. Worse they can plan their own scam exits. We can not know they actually were hacked, bankrupted or just scam exited.
We are only able to control where to store our coins. The best is in non custodial wallets. Even so, we must back up our wallet as it will be used later if we need to recover that wallet.
Withdrawals will largely stop until the market is stable.
Withdrawal can be delayed, halted for a while when a network is congested or with technical issues like altcoin blockchains usually have.
However what you discussed is different, with bear market, over leverage and liquidations on venture capitals, institutional investors, many platforms are in bank-runs and some of them are going to be bankrupted. Hence they disable withdrawal and maybe not temporarily but forever. It does not relate to mempool, network but financially related to those platforms and their left-over available capital.