what are the benefits/limits of constructing AEAD using Duplex mode with ARX primitive (chacha20 for example)?
It is possible!

The SPARKLE suite is a round 2 family of NIST candidates that uses ARX-based permutations to build sponge-based hash functions (called ESCH) and duplex-based AEAD (called Schwaemm): see their website and the NIST list of candidates.

Some advantages of ARX would be the smaller code size and the speed it allows. A disadvantages would be a harder masking (an implementation technique preventing side-channel attacks).