Below Y: "-3" (in the void) in all dimensions you can't use rocket fireworks to boost yourself upwards (when having Elytra equipped).
This bug is consistent with creative and survival and it is a Bedrock exclusive bug
Y: "-2" and below also has issues with bow, fishing rod and ender pearl usage.
Thank you for your report!
We're actually already tracking this issue at MCPE-44241, so I will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
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