There are definitely many downsides to BGA's Elo system, including that using 1 set of k-factors regardless of game will lead to many poor choices of k-factor across all BGA's games.
This Elo system is also quite poor (I'd argue in a worse way) when adapted to multiplayer games because multiplayer games are usually not a combination of all the pairwise 1v1 matches.
The only solutions for now are to care less about your rating and/or use the long-run range of ratings that you find yourself in instead of your Elo at any exact moment.