Last month, Comcast released a paper Improving Latency with Active Queue Management (AQM) During COVID-19 that shows that their PIE AQM dramatically decreases lag/latency (by a factor of 10X — from 250 msec down to 15-30 msec.) From the paper (page 13):
… As explained earlier, for two variants of XB6 cable modem gateway, upstream DOCSIS-PIE AQM was enabled on the CGM4140COM (experiment) variant but was not available on the TG3482G (control) variant during the measurement period
At a high level, when a device had AQM it consistently experienced between 15-30 milliseconds of latency under load.
… [The] non-AQM devices experienced in many cases 250 milliseconds or higher latency under load.
See if you can get an XB6 / CGM4140COM cable modem