Greetings VRChat!
Speedify does not work with VRChat. I’ve tried all settings.
Speedify is a networking/VPN tool that allow you to combine multiple internet networking cards that have access to the internet to make your internet connection more stable and redundant. See their website at speedify.com
This is a tool that has surfaced rather recently and it’s super useful for me as i’m currently residing in an area without direct fiber. Also, I stream a podcast in VRChat and it is therefore a tool that is critical for my continued live streamig hobby.
VRChat devs: I will let you borrow my premium account if necessary. But I think the free version should suffice. It let’s you combine more than enough networks from different or same provider but limits you to 2GB of data 
Some additional technical infromation:
Basically, this tool works like a VPN. It connects all your networks up to their vpn with ease and combine their total bandwidth to a virtual network card.