Assuming use with a dedicated power meter, the main thing you can play with on the resistance side is “how fast” you are spinning the rollers based on the gearing you use.
- If in a low 1 setting, and you may have to use higher gears to hit something like 300w.
- Swap to 3 setting, and you may be using lower gear to hit that same 300w.
This all goes down the road of using the trainer with a setting that mimics the feel of what you expect outside. Faster gearing for fast road riding, Slower gearing for stuff like MTB and gravel.
It’s a bit like the gearing selection in ERG discussion. You have the ability to tweak the feel to your needs.
Does that make sense?