If no solid evidence to prove the legitimacy of these two paid accelerators, no one should use both of them if you want to avoid scam.
Recently I have also seen the bitcoinjumper.com site, had a problem with one of the members here, to be precise the incident occurred on June 17, 2023.
bitcoinjumper.com Bitcoin Transaction Accelerator is scam do not use this fake service
It seems, anyone should be careful using the bitcoinjumper.com service, to prevent losses and avoid fraud and so on, it seems that it is a legitimate warning about a scam.
For the BTCNitro site, it seems suspicious too, they have a thread here:
https://bitcointalk.org/index.php?topic=5288307.0, what is fishy to me for a BTCNitro service site, is what @SFR10 suggested, they didn't heed it, they posted something else.
Looks like BTCNitro, also a service to watch out for, before any trouble.