Hi !
Although this a duplicate, this issue needs attention and it's so disastrous that it effects a huge chunk of Minecraft Bedrock players.
That said, the issue is that versions with Render Dragon decrease performance to ~8.7ish fps from ~56 in versions with no Render dragon.
I don't say that the devs need to remove Render Dragon, I want them to improve it and optimize it to match older versions in terms of performance benchmarks.
Also if you read this, respond with a message explaining why this issue occurs or how difficult it is to fix it 😉
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Please do not intentionally create duplicate tickets. If you would like to show your interest in an issue, add a vote to the main ticket (MCPE-142934).