It only allows me to play a demo world, and it says I have to download Minecraft again, which I have done several times already and its still a demo world

Please check out this help article: https://help.minecraft.net/hc/en-us/articles/360029643892-Can-only-play-Minecraft-demo-Java-Edition-

If that doesn't solve your issue, please contact Mojang Support.

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Thank you for your report!
We're tracking this issue in MCL-16570, so this ticket is being resolved and linked as a duplicate.

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📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
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