FlowG is more inspired by OpenObserve, and its main feature is visual scripting pipelines, where you can parse/mutate logs using the Vector Remap Language, categorize them, route them to different streams (or store nothing at all and forward the logs to third-party services).

It is in my opinion and experience, simpler to setup than Graylog / Loki, and especially simpler than Logstash. In fact, it overlaps a lot in terms of feature with Logstash, with the disadvantage of being younger, with a very (very) small community, and far less documentation.

I haven't written a deeper analysis of how it compares to the "competition" (if we can say that in FOSS...), the project mainly started out of frustration with OpenObserve and to scratch an itch.

I hope this answers your question.