For that price, you could get a Leicaflex SL (or maybe even an SL2) + a CLA.
The R6 is a nice camera (better viewfinder than most) but IMHO not that special.
The Leicaflexes mentioned above *are* special...
(Big, heavy beasts, but the R lenses themselves are big, heavy beasts).
About the Leicaflexes being 30+ years older than the R6, if CLA'd the'll certainly outlive the newer camera (watch out for prism de-silvering on the SL - though also fixable within that budget).
Even the *terrible* obsolete battery problem many mention is in fact no problem at all and has several good solutions.
Not personally familar with that 50mm, but it should be excellent.
Leica lenses need to be looked at case by case. Some are simply good (a very few even average) and some are exceptional.