how to adequately convert a bedrock model for java

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I had a good model like Bedrock Entity. I needed to convert it for Java, but the output is this result.

How can I convert it properly? What should I do?

[fierce lintel]

that is alredy converted "properly"
different formats have different restrictions, if a model deosn't adhere to the restrictions of the new format already they will be enforced, hence that result

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so there is no way to fix it?