I'm not even sure you need to pretend you were working. Especially mid-career, taking 6 to 12 months off to consider your options, do some learning, etc. isn't something I would think twice about as an employer.

"gaps in your resume" is actively used to cover over-40 hiring discrimination in tech jobs

Fair enough for some situations. I guess it helps that I've never had a job since school where I came in through HR as opposed to someone I knew.