Leaves look firm and structured, no puffiness or drooping. So at least I would not suspect waterlogged roots or too wet substrate.
The main issue seems to be a mild CalMag deficiency, likely because of soft water combined with organic soil.
A good move could be:
Add a light CalMag supplement to the next few waterings (low dose, around half strength at first).
Keep pH around 6.2–6.5 to support calcium and magnesium uptake.
If no CalMag is available, a homemade alternative could be a very light Epsom salt (magnesium sulfate) solution: about 1/4 teaspoon per gallon (approx. 1.25 ml per 4L) – but this only fixes magnesium, not calcium.
Long-term, a balanced CalMag product would still be better.
No need to flush or reset anything – the plant is stable. Just gentle corrections and patience.