Stuck with Trial version only.

When you are re-downloading it there might be an option to download the trial version that you are selecting instead of the full game. I know ive had that issue before where i swear i was downloading the full game when i wasn't.

Delete the game, remove the purchasing account from the console, reboot the console (hold the power button for 10 seconds while the system is on), re add the account, download the game again.

Hey there, try uninstalling and re-installing as that should reset it as it will install as the disc. If that doesn’t work if you are using a external device to store your games try deleting it from there.

... I have indeed obtained the game through legal means I got the game when I bought Minecraft Java. [...]now cannot play it because I cannot sign in [...] please help!

The "ownership" of the Windows 10 Version of Minecraft is determined by being signed in to the Microsoft Account that you used to redeem the code you got from the Java Version.

If you are unable to sign in to your Microsoft Account, you can't access your license.

So we need to troubleshoot your sign in issue first.

What prevents you from signing in? Are you getting an error message? Are you able to sign in on
https://account.microsoft.com?

If so, can you go to
https://account.live.com/Proofs/Manage and check if your security information (i.e. secondary emails, phone numbers etc.) are up to date and accurate?

While already there, make sure that you have Two Step Verification enabled, and the Authenticator App set up on your phone.

If you are able to sign in on your Microsoft Account on these pages, make sure that you use the same Microsoft Account to sign in on your Windows 10 device.

Uninstall Minecraft from your computer, and then on the store install Minecraft for Windows 10 again.

Try using a different account and go on minecraft to see if it ended the trail. Or you could, use someone elses xbox and try to sign into your account and see if minecraft ended the trail.