Which offers the best Mikrotik performance PPPoE/Radius or IP/MAC/API

My company manually sets speeds on Ubiquiti customers radios but is trying to migrate to Splynx. They are now doing the billing with splynx and we’d like to have splynx manage the authentication and speeds. I’ve managed several scenarios with our Microtik test router with PPPoE authentication with RADIUS. I was asked to test the setup on a small mikrotik to see what kinds of loads the PPPoE customers would generate, a speedtest with PPPoE with 20/10Mbs down/up made the cpu load on the Mikrotik jump to over 50% while resting is 2-7%. Disabling the PPPoE and reconfiguring with IP no speed control we got 100/100Mbps up and down the max load was 25%. With 20/10Mbps using radio to control speeds it was 3-8%. We have 300 customers about 30-40 for each AP so this could be an issue if we use PPPoE particularly with 1 central Mikrotik. I suggested we put a Microtik for each AP to handle the 30-40 customers each and of course use something more powerful than a HAP Lite (my test equipment), so we are considering this option. The MIkrotik that handles the customers is a much more capable model. But does anyone know if directly using IP/MAC authentication and API control from Splynx will have better performance. I did look into using SNMP to control the Ubiquiti devices, and they don’t support much of anything worthwhile in the SNMP realm. I have managed to get usage using ssh /usr/www/status.cgi with these devices but didn’t see much in the way of commands to change speed. So back to splynx… does anyone have an idea what setup offers better/scalable performance. At least between API/IP and RADIUS/PPPoE or any better option.

Thanks in advance…