The MDM profile is what is controlling the updates restrictions.
If this computer belongs to a company, then you should not remove it.
If you bought it second hand, then removing it will simply release all the restrictions it placed on it.
You either remove it, or you live without being able to update the macOS version until whoever controls the MDM and is by definition managing the computer allows it.
The real question you need to answer, is why is there an MDM profile on your computer. As said if it belongs to your office, then you have o right to remove it.
If it was bought second hand, and someone forgot to correctly wipe it, and remove the MDM profile then that is something you should consider doing, to make sure there's nothing else left over from whoever owned it before you.
MDM profiles are not installed by default, so unless you manually installed it yourself, then there's no reason for it to be there if you own the computer yourself.