Gotta keep your webview up to date! There's alternatives as described in the comments but yeah, having a version of Chromium older than a year old is pretty dangerous/insecure.
I think most 'normal' android users never really think about it because Google keeps their webview up to date automatically, but if you dont use Play Store this can be easily overlooked. Really important for device security though.
Edit: As for why Voyager requires System WebView >= 140... Android recently overhauled safe area insets and thei rollout was kinda botched with poor backward compatibility. This is a side affect unfortunately.



