From a candidate's perspective, there is no upside to giving an extended explanation of a recent gap on your resume, for the same reason there is no upside to giving an extended explanation for why one left.
"I took a quick break to recharge before the next adventure."
"I had some projects I wanted to explore for a bit."
Immediately move on.
Family member died? Bringing that up doesn't help.
Volunteered for a school? Bringing that up doesn't help.
Worked on a novel? Bringing that up doesn't help.
Failed fast? Bringing that up doesn't help.
No answer to that has ever convinced an employer to extend an offer, but a lot of answers cause employers to Nope out of particular candidates.
b) You're transgressing the No Backstabbing rule.
I'd just straight-up steal @tqbf here: news.ycombinator.com/item?id=9930311
>> I feel like I contributed everything I could contribute to that team and now I'm looking for a new challenge.