Thought I’d provide an update on my progress for posterity.
I haven’t fully solved the issue yet, but I’m finding far more success using nkast’s final suggestion of rendering everything on a rendertarget and scaling, including keeping a consistent aspect ratio. I’m then setting the TouchPanel DisplayWidth and Height to the world size and it finally worked as expected on my friend’s phone. It’s not 100% accurate right now yet because I’m not accounting for the black bars present when accounting for a consistent aspect ratio, but I feel that this is the most progress I’ve made in a while, it’s using base Monogame tools, and it’s a solution that I feel I fully understand what’s happening and why it’s happening. I’ll keep working at it until it’s perfect though.
Thanks again for all the help everyone.