be careful when you face preposition AT/IN after the word (succeed)
the general rule of that is not regarding the word succeed, but it depends on the object
for example:
He wants to be succeed (IN) speaking English
in this example we talk about specific situation which is SPEAKING ENGLISH
We also can use AT
He wants to be succeed (AT) life
in this example we talk about a general activity.
I wish you all the best of luck...