I finally got it setup correctly, but my speeds are very slow. Around 7mbps down, 0.15mbps up. Probably just a limitation of my router, if I had to guess?
AR9344 is not great but it should be capable of upto 10-14 mbps download/upload via ethernet (it will be slower with wifi) in my experience of this SoC.
I found a tutorial for WireGuard, and my speeds improved to 22mbps down and 13mbps up. I think my router just isn't good enough to handle OpenVPN. I only really needed the VPN for changing my NAT type (TM-HI is weird, and their router doesn't have port forwarding)
My ISP is T-Mobile Home Internet. My typical speed is around 93mbps down and 94mbps up.
Windscribe VPN has an option to pick the best VPN location, and that's what I used. So, it's the fastest server for me.