Is abstaining from a Qur'an memorization center that focuses on Tajweed and Tafsir rather than memorization, and returning to self-memorization at home with greater concentration, considered a whisper from Satan?

Your departure from the Quran memorization center does not necessarily mean it was a whisper from Satan, as a person may err in estimating what is best. It is better for you to connect with a skilled female memorization teacher (muhaffizah) who is proficient in the rules of the Quran, because you cannot identify all your recitation errors without one. Ibn Al-Jazari stated that the Ummah is obligated to correct the pronunciation of the Quran and establish its letters according to the manner received from the imams of recitation. And whoever is able to correct the words of Allah Almighty with the correct pronunciation and deviates to the corrupt, then he is sinful. As for someone whose tongue does not obey him or who cannot find anyone to guide him, then "Allah does not burden a soul beyond its capacity."