I already have bought Minecraft Java edition. How do I get MCPE?

You will have to Purchase Minecraft Pocket Edition, as there is no way to get the game for free if you have the Java Edition. That offer is only for Computers with Windows on it. Depending on your phone, you can either purchase from the Google Play Store, or the Apple app store.

I bought the Windows 10 version of Minecraft by mistake, but the one I wanted was the java edition.

I saw that anyone who buys minecraft java edition is entitled to minecraft Windows 10. Is the reverse also true? Who buys minecraft windows 10 is entitled to minecraft java edition?

If so, how do I access the java edition version at no additional cost?

Can I get Minecraft: Java Edition for free if I bought Minecraft: Bedrock Edition and i linked the Microsoft account?

No. The java and bedrock edition are completely separate from eachother so if you want the java edition you will have to purchase it

Source: me. Its what i had to do.

Also again my order history will NOT say I purchased Minecraft because I did not. As stated before, I got minecraft bedrock because Mojang gave a free code to redeem Bedrock for all Mojang users that purchased Java Edition before a certain date see article below:

How do I get free bedrock if I have Java? (wikilivre.org)

"Windows 10 has the legacy Java Edition as well as the modern Bedrock Edition. If you bought the Java Edition before October 19, 2018, you can redeem a free copy of the Bedrock Edition. You can also buy the Windows 10 edition directly from Microsoft for $20."

I did redeem this code, so again what gives?

I bought Java Edition on 24 May 2022. But I refunded it.

I bought the Minecraft: Java & Bedrock Edition for PC (the Bundle, released two days ago) on Minecraft official website (https://www.minecraft.net/en-us/store/minecraft-java-bedrock-edition-pc). on 8 June 2022.

I have uninstalled the Minecraft Launcher and reinstalled it.