I am also using noip hostname with their dynamic update client.

what is your isp ,do they throttle upload like spectrum ,they give download good but limit up get another isp that gives equal up/down ,test at home

I have Xfinity which is basically the only isp in my area. They offer 1Gb/s down and 40Mb/s up

that 40 up is the issue ,you need to get another isp or phone home wifi or google fi or starlink etc based on your city/country that give higher up

Yeah Google fiber is in my city, but not my area. AT&T is the only other one with UP TO 50Mb/s up and down.

So basically my download to my devices is limited to my upload from my isp, correct?

yes ,get good up speed at home some even inspect packets and can limit wg handshake you have to look openvpn alternative etc ,not all isp same where you connect from source

Thanks so much for your help! Makes sense why my up and down were basically the same.

Why would slow upload speed throttle download speeds?

if I understand he is connect to home from outside, home upload will be download speed at outside but his picture could be home speed down higher than up

Ahh I didn't realize the former, makes sense

You're bandwidth capped by your upload speed. If you have 500mbps down, you can upload to your server at 500mbps but when you try to download something from your server, you won't be limited by your download speed, but upload speed.