Steamer600, which assumes 450 plate appearances for each catcher, projects 2019 WAR of 1.7 for Josh Phegley, 2.0 for Oakland teammate Chris Herrmann and 0.2 for Blake Swihart.
Among all catchers in the projections, Phegley ranks No. 32, Herrmann No. 21 and Swihart No. 209:
https://www.fangraphs.com/projections.aspx?pos=c&stats=bat&type=steamer600&team=0&lg=all&players=0&sort=27%2cd