Glad to hear it was just a traffic shaping thing. You could certainly leverage traffic shaping to perhaps 5 or 10Mbps per client along with SpeedBurst enabled and you can adjust that SSID-by-SSID. You could also take a more "global" approach via traffic shaping on the upstream MX. Regardless, I wouldn't leave ALL traffic shaping completely disabled, but it depends on your deployment and users.
Also, as @MRCUR pointed out, see if you can consolidate the two NAT mode SSIDs into one since they're really doing the same thing. Depending on how many clients you'll have on those SSIDs, that could certainly save some resources on the AP (NAT tables, etc) as well as improve the RF, because every additional SSID is going to consume additional airtime, beacon at the lowest mandatory data rate, etc. Try to stick with the general best practice of minimizing the # of SSIDs.