I understand that the better form of the sentence would be:
Success is determined by how determined you are to succeed.
but is the sentence I wrote wrong or ungrammatical?
Success is determined by how determined you are to succeed
means
The degree of your determination influences the degree of your success.
You should not use
Success is determined by how you are determined to succeed
to mean this, because the latter either means
The way you find determination to succeed influences the degree of your success
or
Success is determined by how you define success.
The two sentences can be both grammatically correct, but there are three different meanings here.