marrrko I would like to know who you consider to be industry leader in SEO?
From my experience nobody.
Why?
Because we all speculate how SEO works, nobody really knows and that's the fact.
Some very big Australian companies asked us many time for advice and how to handle some things. I was very, very surprised at first but on second thought all was clear for me (i will not post explanation how and why) .
That's why you are here. You got ranked, you got slapped and that can happen again and again and you can not do anything about that, nobody can.
I read few blogs, about real businesses, real people and real stories. They all got slapped recently and they play by "rules" 100%, real links from real sites, very good ONpage, extremly quality and informative articles, very old domains, no spammy links at all, not links from competitors etc. On the other side (you probably heard) many spammy blogs so called buffers ranking very well. You got my point.
My thoughts regarding your issue, remove all bad links, start your campaign with less amount but extremely quality links and put much more effort on socials. Wait and see what will happen.
Try to build your own PBN. Grow it by time, and you will get back on track for sure again.
How long it will last, god knows.
For all these your budget is good enough.