I don’t know whether low shbg is bad or not. Mine has been around 2 for years. I do know through running blood work that I need to pin frequently to keep levels stable. Even 2x/week on ester I’ll have large peaks and dips. I pin ED or 3x/week.
Extremely low SHBG = faster metabolic clearance rate of Testosterone (or any AAS actually).
This means that more frequent administration is advisable. Hypothyroidism can worsen the issue, so might overt low E2.