SSL cannot be the reason for such a drastic drop. It is a minor ranking signal, I'm sure of that. Don't nit-pick or you will go insane.
If SSL was really a problem then you would experience a sudden drop when algo was updated to give ssl more weight, but then rankings would normalize. But the drops happen every day gradually for weeks now, so I'm pretty sure it's not SSL (at least not a major thing).
It has to do with re-evaluating websites and their intent. If it is a general blog where you also publish "fashion", "beauty", "lifestyle" topics then you will not be able to rank for "serious" health related keywords. I think that's the thing here.
Authorship and EAT of an author is just snake oil. Authority of a site is determined from backlinks it receives.
Here's an example I've seen in my case.
Keywords related to blood pressure.
I've ranked high for many of the keywords, but I have a general health blog (I cover many aspects of health, but also aspects of lifestyle, beauty etc). Now my site is overtaken by private clinics and high authority website such as healthline for specific keywords related to blood pressure. It seems that google looked at my site and established that I am a blog, not a "serious" website, therefore I cannot rank for YMYL keywords, while some clinics and high authority websites can because they provide more value to the search string "blood pressure". Think about it - i have a high blood pressure and I look it up on google. I might as well land on a clinic site that offers "lower your blood pressure" programs but also offer information on high blood pressure instead of landing on a general blog from where I need to click further to some clinic to being my treatment...
That pushed me down the serps severely. On top of that, sites with good links also overtake me as they have less relevancy, but better links, so I'm sure it was an update on links too.
I will not talk about sites sitting on page10 as they're obviously some black-hatted websites and are there because of google serp exploits (otherwise I see no reason why they would over-rank my site). So this is what happened probably.
We will see in time if this move is good and I'm sure google measures carefully the bounce rate and time-on-site parameters for newly established rank1-10 websites to see if it improved. Not that all that matters is bounce rate and time-on-site, but its a good indicator.