MCDHU:
Troubleshooting does not always necessitates a level off. Have you thought having an engine surge during climb while below MSA ?
Why would you level off and disconnects the autothrust to check the engine health at low power setting for a speed of 210 kts?
Have you thought of keeping climbing at a higher speed ( to reduce your rate of climb) and checking the faulty engine from idle to climb power? By doing so you will only increase or reduce your rate of climb when retarding or advancing the lever.
No need to level off , no need to check the engine health at 210 kts as it is not relevant as for the continuation of the flight , or you just get a partial picture of your engine , which undoubtedly calls for innovation like mentionned , autothrust off.