How do I install two different versions of the same application on SteamOS 3.0, an Arch Linux based OS?

Got a steamdeck recently and have been setting it up for emulation. It's running SteamOS 3.0 which, from what I could find, is based on Arch Linux. I need two versions of PPSSPP. The latest build for most of my library and v1.10.3 specifically to play Phantasy Star Portable 2 Infinity over the internet with friends. I'm able to downgrade the currently installed flatpak to this version but now I've hit a roadblock trying to install the latest build without overwriting the other. Having never used Linux before in my life...I'm lost.