what happened to the community made map packs and stuff like Half-Life Source?

[JS101]

In the 2024 megabuild, they are missing, and when trying to install the [CUSTOM] hls it just crashes the beta.

[science_team165]

In the 2024 megabuild, they are missing, and when trying to install the [CUSTOM] hls it just crashes the beta.

because there is a lot of code change in the new megabuild that makes the mods incompatible

[JS101]

because there is a lot of code change in the new megabuild that makes the mods incompatible

ah alright, thanks!

[Shift]

Wrong.
They're not included because megabuild was rushed to meet the anniversary date, and those mods literally don't contain any extra code. They can still be downloaded and installed separately from the site.
If HLS crashes, installation likely was incorrect.