Running older Windows malware - is it still unsafe?

[CattailAle]

I have many Windows executables from the 2010s I want to run and it's possible one or more might contain malware.
Since they are this old, they cannot be using working unpatched exploits to escape the bottle and the flatpak sandboxing on an updated system, correct? Or can they?
What's the worst that could happen if I run malware this old on a bottle without networking using the default Bottles flatpak permissions?