How to explain job gaps on the resume?

I’m interviewing with several companies for SDE roles and have a gap of > 12 months since my last job. Is this a career killer and a huge red flag for any hiring manager? The real reason for a break was medical but then got out of hand given i had enough savings to support myself and sort of slacked for a while (like 3-4 months). What is the best way to mitigate this issue when applying/interviewing?