[300bps]

ISP's router [...] Put it into modem mode and pass all the packets straight through to a third-party router.

Best thing I ever did. Put in a Linksys Deco X55 mesh system with WiFi 6 system.

Have four of them strategically placed throughout the 2,500 square foot house and have perfect coverage on a single SSID.

My iPhone 13 gets a bidirectional 360 Mbps just about anywhere in the house (the limit of my $39 per month FIOS line).