" I don't have the muscles for the bellows"

Fallacy - you can get very small ones - please read the thread recommended... with less than 120 basses ('folk music' 'needs' far less) - teh ssmaller, the easier, but you have built up the muscles for playing the piano over - how many years? - so you will just need to build up teh 'bellows muscles', same as yo would need to build up tehsets ofmuscles for ANY new instrument.