Convincing boss I need time off?

This new norm has me feeling that there’s a lot of blurred boundaries, increased child care responsibilities, feelings of isolation. Furthermore, our team is strapped thin. Layoffs happened and I’m now doing the work of 3 other people who were let go. So essentially, I feel really guilty asking for time off because I’m lucky to have a job — and know I’d be overwhelmed with work when I come back unless I have a OOO plan that includes people who aren’t even in my department to help cover me. I need a moment to just be with myself, spend quality time with family, or try a new hobby to reset. And I know I need to checkout in order to perform my job better. How I convince my boss that I need time away from work? And how do I to make begin an OOO plan when there are no long people within the company to help cover me? Advice/thoughts on either question would be wonderful! Thank you.