R7800 wifi much slower on 18.06.1

I was running 17.01.5 and getting wifi speeds of 110+Mbps with these Intel wi-fi iwlwifi options (sudo nano /etc/modprobe.d/iwlwifi.conf) enabled in Debian: options iwlwifi 11n_disable=8

Since switching to 18.06.1, my wifi speeds have dropped to 55-65Mbps with or without the iwlwifi options enabled.

Anybody know a way to get my speeds back up on Debian? I'm using Debian Stretch with R7800 Netgear router.