RPi4B USB Tethering SLOW


I am using USB Tethering on the RPi4B. Tethering via my iOS device. I followed the smartphone tethering guide and another forum post to improve the performance such as installing irqbalance package and enabling packet steering. I also changed the irqbalance config to enabled "1". The issue I observed is that the speed given through the RPi is 100Mbps tops and when connecting via the iPhone directly, I get close to 200Mbps+ speeds. There was a forum post which mentioned changing the TTL on the firewall, I tried that, and I observed that the speed actually reduced to 75 Mbps!

Can you please suggest on how can I get faster speeds on the RPi? I'm using Wifi AC and on 5ghz band.