Sadly, I'm no expert. I've dabbled, but the long and short of it is, along with on page factors, is Google is fundamentally against active SEO. So any "experts" will eventually get you sandboxed or you'll lose your new found ranking.
The trouble is Google is far more intelligent than you or I, and the algorithms they have in place to spot it are neither shared nor known and many proper SEO people will guard their testing closely as it will give them a bit of an edge.
I suspect the biggest issue is things like using Webmaster Tools (Search Console) as it could be speculated that if you're actively monitoring your site, then you're likely doing SEO and in essence are providing Google with a big red flag from the get go.
It could further be argued that as you monitor bad link alerts and things in WMT, the way you react, and perhaps disavow links, will tell Google a lot about what you are or are not doing in terms of SEO.
If bad links, and lots of them, could always negatively impact a site's position in the SERPS, we could all go Google Bowling and take out all our competition by sending 50,000 Xrumer links from forum profiles and bad neighbourhoods.
There's shit loads of speculation and even more "experts" who are simply snake oil salesman who long term will perhaps cause problems.
Moz is arguably decent, and publishes good stuff, but a lot of people will tell you Rand Fishkin is full of shit and talks a good game. I've always considered Tommy Griffith and Neil Patel THE experts. I'm aware that the ClickMinded SEO course (Tommy Griffith) is considered superb and I believe is available by torrent. Much the same I'd guess for Patel's Quick Sprout stuff.
I no longer game Google and barely do SEO. I just keep the onpage tight and pretty much ignore all else. I ranked a site top on a VERY competitive term, from doing only that.
I went to seminar many years ago and an SEO gave a talk where he said that if you're legit, that's all you want to do. Do that and publish good fresh content on your site (and elsewhere) and you'll be grand. Allow natural growth and link patterns, because when all is said and done Google knows more and sees more than we can ever possibly grasp or hope to reverse engineer. In my opinion, idle speculation and following the newest SEO trends are a route to being lost in the serps.
Jesus I've babbled.
I'll pm you, unlikely tonight. And I'll get my Skype turned on for you as well!
Have a look at Patel's blog.
https://www.quicksprout.com/blog/ I'm sure some intelligent speculation can be found here as well.
https://www.serpwoo.com/blog/ 
