@luanne, any WordPress plugin can be accessed by the vendor from the backend.

Now if you want to restrict this, you must add your own custom code.
Just a query, why don’t you restrict vendors from accessing the backend?

@luanne, As you know, WCMp has rebranded as MultiVendorX, to know more please check https://www.youtube.com/watch?v=bZJxjr7xUew
From now onwards, MultiVendorX Pro (https://multivendorx.com/pricing/), contains all the paid addon’s feature init.

So, in order to migrate to MultiVendorX pro, you may opt for any three options :

Option A

We will share MultivendorX with the module you need. i.e. if you had only Frontend Manager, then you can only use Frontend Manageraddon’s feature in the MuliVendorX Pro.
But you can’t update the plugin after this, as this is one-time solution only.
For permanent results, we would request you to purchase MultiVendorX Pro from here https://multivendorx.com/pricing/ and opt for option B or Option C

Option B

We will give you a coupon discount based on the month left of your subscription, and you can use MultiVendorX Pro
https://multivendorx.com/pricing/
i.e. if you have purchased Advance Frontend of 100 USD and purchased this on 1st January. Then you have left 2 month in your subscription. So you will get coupon code of 100*2/12 = 16.6 => 17
Option C
You can opt for trail version of MultivendorX Pro for a month and based then opt for the Option B
But please note, in order to use Option C, you need to give us some details regarding your site and small testimonial. Only then we can give you API key for the one month free trial.

Let us know which option do you want to proceed with so we can assist you accordingly.