I'm not here to advocate for expensive equipment but my cross country hardtail MTB (even with the wide tires on the roads, non-carbon) feels like half the effor

I'm not here to advocate for expensive equipment but my cross country hardtail MTB (even with the wide tires on the roads, non-carbon) feels like half the effort to pedal than my old crummy commuter trekking bike with narrower tires, so I guess your 600€ bike might already have one of the biggest optimizations packed in ;)