Proposal to use ViaBTC accelerator doesn't make too much sense for at least two reasons. First is that this service (in the free version) can be used only if you pay at least 10 000 satoshi fee, and second is that even with priority option fee on blockchain.com he did not pay such a high fee based on very low fees these days.

If a transaction with priority fee stays unconfirmed for hours, then there is something wrong on blockchain.com with their algorithm that calculates fees.