hello @Chinmaya_Naik ,
we're using fast_accell rules, and I can tell you that not all the traffic is accelerable 😑
search the community, as there was a post explaining how you can look the connections and see what's accelerable and what's not .
in your command you require source and destination specified, at least we're doing it that way.
why you can't specify the source in your case? don't you have a private range that would cover all your sources ? like 10.0.0.0/8 or similar
the addition of fast_accell rules, will not break anything - at least for us it didn't (we did it 3 - 4 months ago) - and you can easily just delete them, or you can just reboot the node (you have to save them in a file in order to kick in next time.....)
hopefully I clarified some points for you 😁
PS: one other way to lower the CPU usage - if you concluded that the ack-up is the one triggering it - you can exclude that traffic from certain inspections - like IPS and others....