There are open source wallets that you can use that support opt-in RBF: Bitcoin open source wallets that support replace-by-fee (RBF)

I have been using Electrum and Bluewallet. I can recommend both wallets. But that does not mean that other wallets are not good too, but just recommending the ones I am using.

RBF to pump fee on Electrum and Bluewallet is by default. If you check mempool site like https://mempool.space/ (for beginners) or https://jochen-hoenicke.de/queue/#BTC,24h,weight (for adviced users) to know the fee priority, you can pump the fee if there is any need to.

You do not have to use those unrecommended wallets that do not support RBF. If you want to make a transaction that do not support RBF, you can disable it on those wallets that support it too. But if no any reason, let your transaction support opt-in RBF.

I have test paid accelerator via ViaBTC before, I could not complete it when I have to pay a fee of over $700 to just accelerator a coin less than $100. Paid accelerator is not what you can like to go for. Always find ways to avoid it, I mean when mempool can become very congested to the extent that free accelerator would become difficult to use successfully.

Also the transaction must not be more than 500 bytes.