Comment # 2 on bug 1208218 from Shawn Dunn

Running

sudo setsebool selinuxuser_execstack 1

Results in the flatpak running just fine.

For a local workaround, you can run:

sudo setsebool -P selinuxuser_execstack 1

And it will remain persistent across reboots.

Review of the policy itself would need to be addressed by the openSUSE Security
team.