I sometimes think viva preparation is like renovating a house.
Annotating your thesis is like hanging wallpaper. Making a summary is like knocking a wall through to let in more light. A mock viva could be repairing the roof, making sure the house is ready in case of a storm.
None of it helps if you don’t have a good house and foundations: your thesis and the research you’ve done to get you there.
Renovation takes time. Viva prep takes time too, but if you feel stretched because of work, because of life, then breathe. It’s OK. Do what you can, and remember you’ve done the hardest part of your PhD.
You laid strong foundations over years of work.