What is the ruling on supplicating for success for a sports team playing in a championship that involves compensation, and does the matter reach the level of disbelief (kufr)?

Praying for clubs to succeed in an activity is a branch of the activity's ruling itself. If the activity is permissible, there is no harm in praying for them. However, if it is impermissible, then praying for success is not legislated and is considered an transgression in supplication. Disbelief has no place in this matter. It appears that the questioner is afflicted with waswasah (obsessive whispering), and he should disregard it, stop indulging in it, and refrain from asking about it.