Installing Android Studio with Kotlin on Linux Mint

When trying to install Android Studio from the Software Manager to begin Kotlin development on Linux Mint I received this error:

"Error deploying: While trying to apply extra data: runtime/org.freedesktop.Platform/x86_64/19.08 not installed"

and followed the advice given here to install the flatpak runtime required for Android Studio:

flatpak install flathub org.freedesktop.Platform/x86_64/19.08

which took ~5 minutes, then failed with the error message:

Warning: Failed to install org.freedesktop.Platform.openh264/x86_64/19.08: runtime/org.freedesktop.Platform.openh264/x86_64/19.08 needs a later flatpak version (1.4.2;1.2.5;1.0.9;)

so I updated flatpak by running sudo apt-get install --only-upgrade flatpak which took it to v 1.0.9, followed by running flatpak update which told me it then needed:

Required runtime for org.gtk.Gtk3theme.Mint-Y/x86_64/3.22 (runtime/org.freedesktop.Platform/x86_64/18.08) found in remote flathub

So I waited for it to do that (but I still need to install x86_64/19.08) so I ran

flatpak install flathub org.freedesktop.Platform/x86_64/19.08