A Google search will lead you to a bad result from services that claim to be free bitcoin accelerators, and all they do is rebroadcast that transaction. Therefore, unless the accelerator is linked to a mining pool, it is either a scam or it is rebroadcasting the transaction.

Examples of bitcoin accelerators:

ViaBTC            ------> https://www.viabtc.com/tools/txaccelerator
F2Pool            ------>  https://www.f2pool.com/user/tx-acc
binance pool    ------> https://www.binance.com/en/support/announcement/boost-your-bitcoin-transactions-with-btc-transaction-accelerator-now-at-a-20-fee-discount-2fd258b5a21b43b29c2f9479428b4acd

mempool.space  ------> (service not yet launched)

Read the conditions for these services first.