I needed to adjust the suggested deps.edn in the Reagent tutorial to get things working.
Bumping the targets for reagent and krell let me get up and running.
{:deps {io.vouch/krell {:git/url "https://github.com/vouch-opensource/krell.git"
:sha "24e2456b4180b16191e21ec79739c31c2e627bde"}
io.vouch/reagent-react-native {:git/url "https://github.com/vouch-opensource/reagent-react-native.git"
:sha "0fe1c600c9b81180f76b94ef6004c2f85e7d4aa0"}
reagent/reagent {:mvn/version "1.1.0"
:exclusions [cljsjs/react cljsjs/react-dom]}}}