HP and CFM aren't related. HP has to do with time to fill (and refill) the tank at to pressure, and CFM is related to air delivery from the tank. HP is just a BS selling point. There's an awful lot of BS in compressor marketing so be careful.
One thing that is related to HP is motor RPM. Since HP is a function of speed, or RPM in this case a 5HP motor spinning at 3450RPM is half the size (and cost) of a motor spinning at 1725RPM. A fast motor is a sign of a cheap system.
CFM is meaningless unless the measurement is provided with an at PSI value. A box fan will provide a huge CFM, but no pressure.
Of equal importance is the air system, meaning anything past the compressor tank. That's the flex line leading to hard lines, coolers, regulators, hoses and air tools. Tools don't live long running on hot wet air.
My compressor: VT-PL-735-80 17CFM@175PSI
https://www.saylor-beall.com/tank-mounted-vertical/
Bought used off the internet...