Resolving pkgconfig dependencies when building flatpak

I am writing a GTK Rust program and I am able to compile it with Meson. I am trying to compile it into a flatpak but it fails with CMake dependency errors.

It is coming up with Run-time dependencies for ‘gnome-autoar-0’, ‘gspell-1’, ‘libcanberra’, and ‘goa-1.0’. I checked dnf and installed all the dependencies and their devel versions. This didn’t work so I also ran commands like
dnf install 'pkgconfig(goa-1.0)' and it came up with
Package gnome-online-accounts-devel-3.38.0-1.fc33.x86_64 is already installed.

It says it is Using 'PKG_CONFIG_PATH' from environment with value: '/app/lib/pkgconfig:/app/share/pkgconfig:/usr/lib/pkgconfig:/usr/share/pkgconfig'
But it still cannot link it to the libraries. Looking else where I think the *.pc files for the packages are missing or in the wrong place.
Can someone help? I think this is a packaging issue, but it may be an issue somewhere else?

p.s. I’m on Fedora 33 and /usr/share/pkgconfig is the only directory that exists.
My flatpak settings are
runtime: org.gnome.Platform
runtime-version: master
sdk: org.gnome.Skd

It looks like my issue was with run-time version: master.
I changed it to '3.38' and added sdk-extensions: - org.freedesktop.Sdk.Extension.rust-stable

I’ll check if it’s a bug with master and worth submitting an issue.