What the graphs show is that when taking into account age, education, and so on, that public sector workers have enjoyed a pay premium over private sector workers for at least the last 30 years. If the shoe is on the other foot right now then it's the first time in decades. And that's before taking into account final salary pensions etc., which are unheard of in the private sector but still common in the public.
It's quite probable that public sector workers will get a pay rise, and there's a strong argument that the tax take will rise significantly with inflation so it could be afforded, but I will say that this pay rise isn't going to make public services any better (it may not make them worse). That's a central concern around the stagflationary predictions at the moment, that things are getting more expensive but productivity is continuing to flatline, as it has for yonks, and so we get the worst of both worlds.