Is it considered disbelief (kufr) if I intentionally or lazily miss one prayer and do not intend to make it up, based on the opinion that intentionally missed prayers are not to be made up? And is adopting this opinion because it is easier, or due to doubt about the prayer's validity, considered disbelief or a blameworthy pursuit of concessions?

Fatwa no. 99266 clarifies the ruling on one who abandons prayer out of laziness, and consequently the ruling on their disbelief according to those who hold that view. Fatwa no. 116315 explains the ruling on making up prayers missed due to ignorance. The majority of jurists do not consider one who abandons prayer out of laziness to be a disbeliever, and they deem making up the prayers obligatory, even if they were deliberately abandoned. Some, however, only consider repentance sufficient. If someone deliberately and lazily missed a single prayer and did not make it up, relying on the opinion of those who do not deem making it up obligatory, they do not become a disbeliever. However, according to the majority, they must make it up. The questioner, who suffers from obsessive-compulsive disorder (waswasah), must focus on treating it and consider the default to be the validity of her prayer, disregarding any whispers of invalidation.