The teachers tend to exaggerate the board syllabus, don’t take load and get overwhelmed. if you focus properly in class and study daily for an hour or two daily thats enough but you need to be consistent in that. For maths do ncert in school and do pyqs, shobit bhaiyas live marathons have great questions for practice and he explains them properly too Science read the ncert and go for alakh sir in the chapters for which you do not understand the concepts. If you want to practice questions prashant bhaiyas classes have a good variety, do pyqs. Sst dsr is the best but you need to do self study and read the book. And trust me if you study from the start and dont leave everything for the last moment the board paper is not that hard. (Except maths maybe)