You're probably confusing 4bet range with 4bet%. There's a big difference.

4bet range is calculated as PFR x 4bet%. So if your PFR is 20% and your 4bet is 10%, then your 4bet range is 2%.

OP says villain "4bets 2.4%" which is really low. If he meant his 4bet range is 2.4, then that would mean his 4bet% is 13.3% which would make this an easy stack off preflop.