Dear Aspirant

I think it's better if you devote much of your time to resources available offline. As going online is very distracting. You may use online resources in youtube for better understanding but make a list of topics for eg 5 topics that you have doubts with, watch them and then shut it down. You may write the topic on the search box and write animation then browse through the list given. You may use Khan Academy.

For Neet

Biology-NCERT is your bible, Read it more than 35 times line to line, figure to figure

Chemistry-Know the concepts of physical chemistry really well, inorganic -again remember the diagrams and read thoroughly there descriptions, Organic-solve questions from NCERT exemplary as well

Physics-Know the formula well, have a clarity of concepts

Finally, solve the last 5 years papers