wRC+ (FG) or OPS+ (BBR) are nearly identical, they are a convenient all encompassing stat of weighted inputs to run creation on a 100=league average scale. They are not the be-all end-all by any stretch, but they are good and convenient, much the way OPS was the nerd stat du sur 15 years ago.
Clearly you know this, but its too early to use much statistical analysis this season. On Monday Wallner had a 200 wRC+ yesterday it was 95, today it’s 77, tomorrow it could be 50 or 150, wRC doesn’t matter. Clearly I’m a Fangraphs guy.