Your RC struggle is very normal and fixable. What worked best for me is flagging the question your struggling with and moving on. Come back to it once you finish the passage. Literally do not spend more than 1.5-2 minutes on it.

Again for RC, more than LR, I found that elimination can be much more helpful. It is pretty easy to eliminate 2-3 answers right off the bat, just by crossing off answers that mention or imply something the author doesn't. As for the missing easy questions, read for structure. Don't try to understand every little detail, this will save time and is actually how the passages are meant to be read.

The most important thing: don't worry about your score right now!!!! Focus on structure, calmness, sticking to a gameplan. Do this consistently and the score will come. After a section or full PT, ask yourself "did I execute according to this plan". Don't ask yourself "did I get the score I want".