You're complaining about XM25 while touting a grocer hobbyist's bad gun design that came straight from the 1500's lol.
Anyway XM25 had no serious lethality problems.
Its main issues were legal. H&K failed to deliver on its contractual requirements for the product-improved prototypes, ATK took them to court, which meant the program was delayed, and canceled as a result of not delivering some 20 improved prototypes with Army recommended changes. XM25 would have gone through another ~30 months of testing had these been delivered on time.
Very likely the PGS prototypes will be one of these improved XM25 prototypes, with the same L3-Harris FCS, and 25x40mm cartridge. It may get a new FCS down the road towards production. It will probably still be issued at a basis of one per rifle squad and stored in the BFV/IAV.