I find at the senior level, scores matter much less - you can be rejected despite getting 100%. I'm not saying ignore leetcode, but it's not enough of a factor to grind for 6 months.
Yes. It's ironic that I've never been 100% qualified (as per job desc) at any job I've been hired for, but never hired for something that I am fully qualified for.
Most places are fine having you pick things up for the job. Some just don't have any better choices.