@malemburg I had similar issues recently and in the past. The TL;DR version is to use an earlier version. I'm including the long version for those searching. They may be helpful for someone.
I'm rebuilding my netboot.xyz onsite to be more in line with upstream and avoid all the customization I built in a previous version. One issue I kept having was the installer would lock up randomly. CPU usage would be high like 80-90%. Unresponsive to input (if the lockup occurred on the user name screen). The issues didn't happen in 22.04, just 24.04. Sometimes it work and then it wouldn't. Google AI suggest it was a kernel issue. Some of the link suggestion didn't really support that claim, but I assumed that it was right. I even built a new XCP-NG 8.3 server and the issue still occurred. In the previous netboot install I used a earlier version of the 24.04 install. I only remember this after Google AI suggest a kernel issue.
So netboot (3.0.0) uses this as it version for PXE install: 24.04.3 and this ISO: ubuntu-24.04.3-live-server-amd64.iso. 24.04.3-717d3a1a/initrd & 24.04.3-717d3a1a/vmlinuz.
When I use this version: 24.04, ubuntu-24.04-live-server-amd64.iso, 24.04-dac09526/initrd & 24.04-dac09526/vmlinuz
After switching to this earlier version all my issues go away. Install is now 100% successful. My autoinstall file works great.
Doing an in place upgrade to 24.04.3 no issues. Works for bios and uefi. So I have a working PXE autoboot that install a new Ubuntu 24.04 with Rust Tools installed. Takes only about a minute to run.