SO should I just ask the casino what format their bitcoin addresses are in? Do they start with bc1 or 1? will they know
bc1 is native SegWit, addresses starting from a 3 are compatible SegWit and with 1 are legacy. If you input a native SegWit address starting with bc1 and your casino rejects it by saying (invalid format), it means that they do not support native SegWit yet. Either use addresses that start with a 3 or 1 to withdraw at that time.