Is the Brook Flashman app safe to use without Brook Firewall?

I’ve seen the concerns about Brook Firewall and the suggestion to use NextDNS instead. Does anyone know if the Brook Flashman app itself is still safe to use without Brook Firewall?

I’m only using Flashman to roam locally in Pokémon GO and wouldn’t be using any of the Firewall/DNS/MITM features. Just wondering if there are any security/privacy concerns with the Flashman app itself.