What’s happening here?

“Most Published Research Findings Are False” —> “Most Published COVID-19 Research Findings Are False” -> “Uh oh, I did a wrongthink, let’s backtrack at bit”.

Is that it?

Yes, sort of. Ioannidis published a serosurvey during COVID that computed a lower fatality rate than the prior estimates. Serosurveys are a better way to compute this value because they capture a lot of cases which were so mild people didn't know they were infected, or thought it wasn't COVID. The public health establishment wanted to use an IFR as high as possible e.g. the ridiculous Verity et al estimates from Jan 2020 of a 1% IFR were still in use more than a year later despite there being almost no data in Jan 2020, because high IFR = COVID is more important = more power for public health.

If IFR is low then a lot of the assumptions that justified lockdowns are invalidated (the models and assumptions were wrong anyway for other reasons, but IFR is just another). So Ioannidis was a bit of a class traitor in that regard and got hammered a lot.

The claim he's a conspiracy theorist isn't supported, it's just the usual ad hominem nonsense (not that there's anything wrong with pointing out genuine conspiracies against the public! That's usually called journalism!). Wikipedia gives four citations for this claim and none of them show him proposing a conspiracy, just arguing that when used properly data showed COVID was less serious than others were claiming. One of the citations is actually of an article written by Ioannidis himself. So Wikipedia is corrupt as per usual. Grokipedia's article is significantly less biased and more accurate.