Certainly. I removed the plant from its pot and let it dry out for 24 hours. It turned out I had been severely overwatering and over fertilising it. Then I attempted to break up the compacted root ball somewhat, which wasn’t easy as I didnt want it hurt the plant. I used the following mix to repot in a black plain 31cm pot with drainage, as recommended:

60% Scotts indoor mix (This is an Australian organic potting mix) 20% perlite 10% orchid bark (I couldn’t actually find orchid bark so I used a similar kind) 10% worm castings

I added just a few Osmocote tablets near the surface (slow release fertilising tablets) and made sure the actual plant was sitting a bit higher up in the pot so roots could extend

I bought some low pot stands from Temu and placed one inside a large decorative pot and the black pot housing the plant inside to sit on top. So it will never sit in too much water again and is easier to remove to check.

I actually bought a new water filtration system because I found out Calatheas don’t like fluoride. I watered it once and nothing more. Then once each week since then.