Netgate / pfSense would have been better off with using a licensing scheme like most (ie. you get CE, and only CE off the website, your home+lab license is paid for ($10/yr or something nominal), and the full enterprise edition is whatever the cost is.
I'm using CE, but I'm considering switching to OPNSense if for no other reason than having Suricata pre-installed sounds really, really good.
Better to have 1/3 the flow than none because you had to unplug the existing fan.
The workload that's described doesn't sound to be too taxing: I'd be surprised if the new fan couldn't keep up assuming the interior is kept clean and the thermal paste/tape has been refreshed.