Why is my Minecraft launcher telling me I do not own MC:Java, a game I bought 10 years ago ?

I'm coming from the Mojang support which has an automatic answer stating that they cant do anything account related. My exact problem was clearly stated by another user on your forum but found no solution : https://answers.microsoft.com/en-us...inecraft/1ff435ef-63e7-4154-9363-5d12f4ee3225

The very confusing recent forced migration by Microsoft already gave me plenty of problems at the time. I indeed had to suffer through 3-days of resetting passwords, create a Microsoft account from my gmail, had to get help from forums to not have an XBOX/MS account connected to my PC because I just didn't want to... I did all that last year only to be able to play for about a week with friends on their new survival server, and the whole procedure actually cancelled my access to Technic Launcher and all the maps I put hundreds of hours in at the time. I got over the complete annihilation of all this hard work and memories, but now, I have a new problem. I'm trying to initiate my gf to Minecraft and we're about to launch a server for us two when I get her her new PC on a 1.12 modded adventure with CurseForge. For that, I had to reconnect to minecraft launcher on my new PC, but when connecting with my newly migrated MS account, the launcher tells me I need to buy Minecraft Java to play it, and can only play the Demo. After all the pain and suffering I went through, would you happen to have a solution for me to finally play the game I bought 10 years ago ? Or am I supposed to put another 30€ in it to be able to run it ?

:)