GL-AX 1800 Flint - Brand New Device Slow Download (only) Speed

I just got a Flint today and my Wi-Fi download speed is horrid compared to what I got with my Unifi UDM before that crapped out. I have ISP speeds of 500/25Mbps and I am getting 15/20 on Wi-Fi whereas with my UDM I was getting upwards of 75Mbps on both my iPhone and Lenovo laptop. I’ve got the most up-to-date firmware 4.10 on the device.

Anyone have any ideas?

Are the two routers using the same channel for WiFi?
Changing the channel on Flint may help.

Both are not plugged in, the UniFi UDM is showing comparison of a different device.

I mean Wi-Fi Channel option.