Moving from
managed dedicated server hosting to unmanaged VPS may prove be a tough decision to make. If you are confident about your ability to handle the challenges associated with server management, you may make the move but be warned that with an unmanaged VPS, you will have to run all the critical tasks on your own. You have mentioned that no one else from your team will be supporting you. This will make your job tougher.
You will have to take a call whether your developer skills are enough to see your enterprise through the tough challenges of server management. The fact that you are moving against conventional wisdom and downgrading from dedicated server to an
unmanaged VPS server hosting means that you will be suddenly burdened with things that you had probably not bargained for.
The key question here is whether you have the time and the ability to do all those tasks that were managed until now by a team of qualified experts from the
hosting service. You must consider the fact that smooth and uninterrupted running of your website is critical for the success of your business. If you have the financial capability to invest in dedicated servers, it is recommended that you continue with the existing arrangement. Managing the server on your own might be a huge gamble which can have major consequences if you are unable to pull it off.