I'm unable to hit pressure on my Flair 58.

If you are not experiencing a clear water leak where the seals are located, a lack of pressure is related to the coffee bed. Due to the Flair 58’s wider basket, the coffee puck will be thinner compared to other Flair models and a finer grind is needed to compensate.

First, grind finer: If that does not work/your grinder does not allow, increase dosage or swap in a “low-flow” (chamfered) basket that has fewer holes to therefore reduce the flow and help build pressure in the basket.