I'm not sure what's meant by using a segwir signature and providing only the individual UTXO?
That is for the PSBT file. PSBT files includes loads of redundant data and stripping it down helps to reduce the size restricted by the communication bridge.
Thank you. To get the input to 20 or less, I can't send more than 0.02 bitcoin at a time. There surely must be a simple way to change this? Any bitcoin amount that is 0.03 or more is 21 inputs. I've sent more than this a month ago so I'm unsure what's changed.
Try if it'll sign with <20 inputs first. Use Coin control if needed on Electrum. I think fees are fairly low right now; would it be possible for you to send two transactions back to an address in your wallet (1x 12 inputs, 1x 13 inputs) and spend it with ColdCard, the two created inputs from the two transactions?
OK yes the coldcard has recognised the transaction at less than 20 inputs, but it would require 6-8 transactions for me to send the total to where I want to. So am I able to open the psbt and delete certain things to reduce the input?