Well, if you interview senior staff, with the same techniques you use to interview junior staff, don’t be surprised, at the results.
I interviewed senior engineers (for a marquee corporation), for 25 years. I have some actual experience, here.
I never made any technical mistakes. Everyone I hired was technically, up to snuff.
The mistakes tended to be in how they worked in the team.
> it would be discrimination if someone else was subjected to a different interview process than yours.
And I really have to take exception to this. Every interview I ever did, was tailored to the applicant. There's absolutely no legal basis for this stance. There's a few "obvious" discriminatory things ("All our girls start in the typing pool," etc.), but people aren't cookies, and "cookie cutter" interview processes are for "cookie" positions. Our HR was very clear on what did, and did not, count as legally discriminatory behavior. HR was run by the Corporate General Counsel, and we managers were required to understand the legal ramifications of our duties.
The OP was talking about senior staff. These are folks that will have Responsibility for significant projects, will need to act as leaders and mentors, and will be the ones to take "point" on the corporate brand and public profile.
Treating them as "cookies" is, in my opinion, less than wise.
If you pit me against some kid, right out of college, that has been spending three hours (of their current employer's time), every day, for the last month, practicing leetcode, you'll get someone that is very good at doing quick, meaningless tests. It won't tell you much about how they'll perform in the breach, or when asked to architect a large-scale, heterogenous system (which is what I'm fairly good at). Not sure how un-discriminatory the process is, there...
In any case, it's all water under the bridge, now. A few companies didn't get me. I doubt that anyone is crying in their beer over it, and things turned out well, for me. All's well, that ends well, eh?