Hello, The trend observed as far is there is no constant weightage given to same topics the consecutive years even though a blueprint can be obtained.For marks wise weightage kindly refer this link https://engineering.careers360.com/articles/jee-main-syllabus-weightage

But start preparing the subjects parallelly so that there wont be huge discrepancy in the level of preparation between subjects. Studying theory concepts alone wont be enough you need to solve problems alongside since the question paper will be more of concept oriented. Divide each subjects syllabus into three sections-

1. easy and requires less time
2. easy and requires more time
3. difficult and needs more effort. You can afford to leave only one  chapter from each subject and not the whole section  to score decent marks. In general you could  spend more time on 11th board problems as more application oriented are been asked from it and master theory  from 12th board . Best of luck