You came from 121kg, so it's not really unexpected that the trip down into sub-90 would have some plateau or even setback.

That's at least 21kg you still don't have anymore, be proud of that! There's also always the factor how our bodies adapt to extended diets (by cutting our daily base burn). That might be one part of your problem.

Hang in there, be positive, if you need suggestions for diet or exercise, we're here.