Need your support to find a good recourses to learn word press themes, plugins development and customization

[Fox92]

I have Keenen interested in learning WordPress advanced customization and custom plugin and theme development. Currently, I have 1 year of WordPress customization knowledge and good knowledge in frontend technologies. How should I start? Can you guys share your experiences related to this topic? I found this Udemy course WordPress Theme Development with Bootstrap in 2021 and some stuff on youtube complete wordpress theme & plugin development course 2021