Elo system for solo pvp leagues
You can’t really use a Elo algorithm for solos in the sense it’s used for guild teams. Guild teams are considered a single entity, so you would have a perfect 1v1 ELO system in this new Guild League, just like in chess.
Solo players, on the contrary, are matched with different players every game, meaning your victory mostly depends on luck. Which means the Glicko 2 system used will only show your skill in a modest measure.