Wave count is practice volume
Every caught wave gives you another take-off, line choice and chance to adjust. A board that cuts your wave count sharply removes the repetitions that help technique become reliable.
The hidden fatigue cost
A demanding board can require more precise positioning and stronger paddling. Fatigue arrives earlier, decision-making becomes rushed and the final part of the session may produce very little useful practice.
Response is not the whole session
A smaller board may feel exciting once you are standing. Judge it against the full session: paddling, positioning, wave entry, control and recovery. One quick turn does not compensate for missing most waves.
Progress with a bridge
Use a modest reduction, a forgiving outline or a board with enough volume to preserve your strengths. Test in familiar waves and compare results over several sessions before deciding the challenge is productive.