Hi @zebra2022 From our Mayo website: “ Cryoglobulins are abnormal proteins in the blood. If you have cryoglobulinemia (kry-o-glob-u-lih-NEE-me-uh), these proteins may clump together at temperatures below 98.6 F (37 C). These gelatinous protein clumps can impede your blood circulation, which can damage your skin, joints, nerves and organs —“

From everything I’m reading about your disease, it’s crucial that you take extra precaution winter to keep your body warm because your blood won’t be able to flow as freely. The lungs can also be involved so it would stand to reason that when your circulation slows down, you won’t have as good of an oxygen exchange in the cold weather.
If you have cryoglobulinemia, it's important to avoid exposure to cold — especially to your fingers and toes. You may want to use gloves when using the freezer or refrigerator. Check your feet daily for any injuries, because cryoglobulinemia can make it more difficult for foot injuries to heal.
Two articles worth reading:
https://www.mayoclinic.org/diseases-conditions/cryoglobulinemia/symptoms-causes/syc-20371244
https://unckidneycenter.org/kidneyhealthlibrary/glomerular-disease/cryoglobulinemia/
Have you tried wearing a mask outside or keeping a gator/scarf around your face to keep your lungs warm while breathing?