oh man I'm so excited for you, the keyboards logic is a world of pain it makes no sense at all
is that an Ernst L Arnold? or just inspired by it? doesn't look quite like an ELA due to the open lyres on the corner, and an ELA would definitely not be a beginner instrument lol
For bandoneon I ended up buying a Bandolica which is a recent argentinian project to modernize the instrument and bring it to a new generation, it's a midi keyboard in a bandoneon form factor, here's a little snippet of me some months ago playing fur elise when I was learning the keyboard hooked up to synthesia