I play guitar, slide guitar, banjo, mandolin, and piano. I have for over 20 yrs now, with a fevered passion.
Im better than most at each (except perhaps piano), and better at all than any ive met. Its my "forte".
That said, banjo is my absolute favorite. I play primarily in 3 different tunings and clawhammer style mostly.
Its the last Instrument I learned but a BLAST to do so! So much fun! Its also easily the easiest to play in my experience. Both physically and theoretically.
I suggest The How and the Tao of Clawhammer by some guy named Patrick. Find him online, free ebook, and YouTube tutorials. Very fun and helpful for beginners.
However, if your left hand is too arthritic, slide guitar or dobro is an excellent option. Also fairly easy to pick up, but you need a decent ear to play the right intonation. If you can sing mostly on key, you'll be fine.
Deering goodtimes are good banjos for most people that never take it too seriously and any acoustic steel string guitar can work for slide, but both should be set up by someone knowledgeable for their intended use/style.
Im left handed. Always played right handed Instruments. Left hand Instruments are stupid and a money waster/option killer.
Dont play left handed Instruments. Just get a normal one. Learning wo t be any more difficult either way as all movements and positions are foreign to you regardless and will need to be trained.
Have FUN! Show us what you get!