I’ve flown with Air France, Jet 2, Easy Jet, Monarch and CCM. Carried co2 cartridges, did have a problem once at Liverpool. That was down to the baggage handling staff who dont work for any airliner, 1 said I couldnt check them in hold but could take them in hand. Easy Jet said the opposite, however I siad I’ll just bin the cartridges so discharged the one in the pump. A baggage supervisor said “what are you doing they are allowed in hold luggage” so in hold they went.
FWIW difference in air pressure from sea level to 40,000 feet is only 15 Psi, every aircraft carries some 150 co2 cannisters in the cabins.
Check before you go with the carrier, if you dont feel confident on carrying them.