Are flatpak versions of Firefox-based browsers less secure?

[LongOblong]

I remember reading that flatpak’s sandboxing conflicts with chromium’s own sandboxing, resulting in them being less secure. Does this also apply to Firefox-based browsers?

[TheDoc]

It seems both Chromium and Firefox based browsers are weakened by Flatpak sandboxing, though Firefox may not be as negatively affected by it compared to Chromium.