What the hell do you mean with relevant? If you think they're a ranking factor like Matthew Woodward suggests, well he's completely wrong on that one.
Only real signals are relevant.
Dont go for fiverr signals (1000 signals for $5 is a joke)
I'm not sure I accept the premise of your question, OP - which is, that social signals were relevant in the first place.
As much as I've tried, I've never been able to get any rank increase from social signals. And, I've never needed them, in any case. My PBN's do the heavy lifting pretty well in most cases.
LOL like Google can tell the difference between real and fake likes/tweets (no they can't) do you have any idea how much extra computer power that will cost to figure that out, you do understand that Google is a business and if apparently very good at making people belief it can see/know everything you do, they can't..... Not by a long shot, and people who do real test know they can't.
So yes social signal are important to justify your backlinks, no google cant see the difference between real and fake tweets/likes, don't belief me test it yourself and see if there is any difference in ranking with fake or real social signals.
Do you even understand how the scientific method works? Uncontrolled, correlation N=1 case reports like that are NOT proof at all.
If you think they're a ranking factor like Matthew Woodward suggests, well he's completely wrong on that one.