I have an iMac from my organization to be used at home. I'd like to reinstall its MacOS, however, when I reinstall it, it takes me to "enrollment server". I guess I need to either take it to my company or somehow connect with VPN. But, Is there a way to bypass that?
No, you shouldn't bypass the Enrollment Server option. I am pretty sure it is related to the MDM setup that you have in your iMac from the company.
Once your company's MDM is connected with Apple Business Manager of your company, it rollout Enrollment in the beginning once it hits the internet.
Your IT department must have something like this that enroll your devices to MDM.
Either your IT admin can give you the password if needed else, it should enroll in the company server without authentication once you hit the internet. Better to reach out to your IT department in this context.
I suggest not to look around to bypass as it is an MDM tool for inventory from your company with company policy.