This is a pretty oddball spin on the former President's activities. I don't think Trump has "gained strength by being marginalized." Since he was marginalized by being kicked off social media, he has become virtually invisible to me. The article claims he unleashed an "onslaught" in April as part of his comeback. But I didn't notice, did you?
From the end of 2016 until January of this year, Trump was a full time resident in my head. Now to the extent I think of him at all, it is almost entirely in the past tense. Trump's support has fallen since he left office, not because Democrats or Independents decided they hate him more. But because Republicans are abandoning him now. Any article about "winning the first 100 days" out of office should at least mention that.