You shouldn’t work on your whole body all at once.
You need to identify where you will see the biggest differences and work on those things first.
There are no days off with mobility work.
Where you say you are pretty tight doing multiple shorter session is the more effective way to start.
Re establishing the correct position and giving your muscles/tissue/joint the positioning the trigger or simulation of the correct position more the longer you will be able to hold the correct position.
You are unlearning your current positioning and relearning a changed position. It can take a little time for the new position to be the default positioning. Just as with changing technique for a skill reinforcing the trigger is an important aspect.
Pick 1 or 2 things to focus on in the morning and pick 1 or 2 things to focus on in the afternoon.
You want to see change with what you are working with.