What is Microsoft doing in that regard? Last I was working on Minecraft mods they did a lot to support them, such as sharing the obfuscation map or making Brigadier open-source. Have there been other developments since then?
The IAM logins seem more like a security decision to me (assumably Microsoft has requirements on how their products need to do authentication), not one to keep away modders.
Ping being to synchronously measure latency of the client - unused by vanilla
Bundle being to force packets to be processed together - very useful for sending clients display animations all at once
And then all the display entities to display text and itemstacks in the air, with custom interpolation and stretching - so advanced animations can easily be made.
The most hostile thing is Microsoft pushing the locked down Bedrock edition.
Bedrock Edition is also iirc insanely locked down in terms of modding and it's the version Microsoft pushes the sales of the most. There's some amount of it possible, but forget about any of the ludicrous automation/engineering mods like you had back in Java edition.
My son and I spent some time making custom weapons and the like using a tool called Bridge (https://bridge-core.app/). It's definitely not as powerful as modding once was in the Java version of the game, but you can do lots of pretty wild stuff with Bedrock if you're willing to jump through the hoops.
One "mod" that recently caught my eye was this one: https://www.youtube.com/watch?v=IUWRK0Jy9d0
Yeah, you have to buy it with "Minecoins", but I can't get too upset that Microsoft has allowed devs to monetize their efforts on the platform. There's still plenty of free stuff available and nothing to prevent kids (or adults) from taking a crack at their own mods.
My son was just recently playing with a site called Tynker, and without any help from me managed to get a custom item into the game, so if an 8 year old can do it, it's about as accessible as you could hope for.
I have always been put off by how commercial Bedrock seems as soon as you open it. But at the same time it sounds like interesting and official modding is available there.