A carbon fork can save around a kilo, which is both a lot and not that much depending on perspective. Personally I prefer the ride characteristics of a carbon fork over a steel fork, so that’s also something to consider. I find steel forks to either be too noodley, or too harsh, or kinda both. Carbon forks more often feel stiff without feeling harsh.

A fork swap isn’t hard to do, but I would be surprised if the cost of that bike plus a carbon fork isn’t more than just buying a bike that already has a carbon fork. Also finding a compatible fork may or may not be difficult. For example if it’s a straight 1-1/8” steerer with disc brakes your options are pretty limited. Also need to keep the forks axle-to-crown height and rake in mind.

Ride it and see. Depends on your personal frame too 😀.

Like I have fluctuated between 94kg and 83kg, depending on my powerlifting or couch sitting routine, so 3 kg on the bike frame becomes irrelevant

My vote is skip it. The potential weight savings is not worth the cost and messing around with.

I feel like the punishment/weight ratio is rather logarythmical, as in it increases with route steepness but not in a linear way - you'll start noticing it on really steep gradients and with tiredness.

If you have a somewhat decent shape and don't ride over too much steep gradients I'll say just keep the steel fork. It's cheaper if you just lose a kilo yourself than in your bike. And depending on the builder, steel frames and forks can feel as flexy if not even more than carbon.

I don't think it is really about weight but more about ride quality. I think it is worth it. STEEL RENEGADE Side note SRAM 1 by systems are pretty cool. Snappy