Of course it is legally correct but there are dozens of ways to get out of it. Some examples:
- If you can show that you are making a significant step career-wise (easy) - If your function is different than when you started and didn't sign a new non-compete (from backend to full-stack) - If the contract is temporary 6 months or 1 year its not valid - If you didn't specify a fine, you need to show evidence of damage/loss of that employee leaving to a competitor (impossible?)
So just a few ways to get rid of it. Almost every (employment) attorney in NL will get this non-compete blown away.
My 2 cents: It costs a lot of (negative) time and if someone wants to leave just let them go. If you respect them, they will respect you. If you screwed them over and over they already copied the data the want and will still leave.
Turn the non-compete to a non-client clause (relatiebeding), way softer but ensures that they can't "steal" your clients. Because you are being generous not limiting the person to move to a better position this clause will be way harder to get rid off. Still be reasonable though :)