@Mjules looking at your nice bufferbloat test results above, I'm using a GL-MT6000. Since we're both Mediatek/Filogic subtarget I figured it would be fun to test with the same settings to check if it's similar...
I'm running a snapshot from last week (kernel 6.1, gcc 13.2). SQM, cake/piece of cake, overhead 22, same dl/ul limits set. Packet steering on, however I didn't do any interrupt pinning, just disabled hardware flow offloading for the test. My cable modem is "gigabit" service rated for 950 Mbps down / 25 Mbps up.
My results are similar, in the 860-890 Mbps range, A+ ratings, +2ms/+0ms, CPU 0-3 all at 40-70% load during max download: