Is it possible to unlock a bundle installed by an ex consultant, who shared and published the bundle on our instance, but has since shut down their consulting services?

Probably not. Was it a work for hire consulting agreement? I'd go back to the agreement to see what was promised.

This was done few years ago before I joined - we tried to reach out to the consultant and they have shut down their consulting service now

Yeah, it is an uphill road for you. I doubt Oracle will unlock it even if you have an agreement that supports your IP rights. The best path is to find a person that still has access to the consultant's account. Is it a company that no longer exists?

Yeah, it was a pretty small company with few folks, and they do not exist anymore. Got hold of one person, but they don't have access to any systems anymore

If it was material to operations, I would leave it alone. Maybe contact NetSuite to see if you can get access, but it is doubtful. If it is not material, just uninstall it.

Its pretty important, but one of the scripts thats part of this bundle is timing out, so we wanted to look at it and see if it could be optimized. Will see if support can help

I would recommend contacting NetSuite and explain the situation. It has been awhile, but I believe as part of the official NetSuite Partner agreement, the company agrees if they go out of business their IP can be unlocked. I am not 100%, but contact NetSuite support for help.

Some bundles are locked and some are open. Is this one is locked and you can't see the code?