Many of our students have arthritis but have still been able to learn piano and often find that regular piano playing has many beneficial effects, with some students reporting that they pain eased considerably over time. For more info - see https://decplay.com/learning-piano-with-arthritis/
The DecPlay method enables you to choose how many notes you wish to play simultaneously, in the left hand accompaniment, so you can make this choice to suit what is most comfortable for you and suits your level of dexterity in your hands. For example you could reduce the number of notes played for each chord in the left hand, to 2 notes or even just 1 note and the song will still be recognisable.