DistantHorizons only releases release versions onto curseforge, because of this their 1.20.4 version can only be downloaded from build artifacts off of gitlab. Not everyone is so technically inclined to setup a modpack and find the correct build for it. This pack bundles together Iris, Rubidium, and Distant Horizons at their latest (functioning) build versions.
It also includes some polyfills for optifine parity:

Noisium for Fast Math related to terrain generation optimisation.
Light overlay for the incredibly useful F7 overlay.
WI Zoom for optifine zoom replacement.

Expect weirdness, bugs, and probably a lot of crashes or artifacting because these are the absolute latest versions of distant horizons. Ill only update this pack if I can get it loading myself! Dont send bug reports in the iris/dh support channels if you encounter issues, as this is a set of mods that are all experimental and probably interfere with eachother a lot, making bug reports pretty much useless.

As a side note; DHv2 and Iris are licenced under lgpl3. Because im re-uploading DHv2 build artifacts & Iris alpha's, I disclose the following:

I am not distributing any modified versions of DHv2 or Iris that function outside the original authors expectations of the software.
All versions of DHv2 that are re-uploaded here are sourced from
https://gitlab.com/jeseibel/distant-horizons/-/jobs.
All versions of Iris that are re-uploaded here are sourced from the Iris Project discord group.
Iris alphas do not release on curseforge, only on discord (for some reason). For this reason the alpha jar has been re-bundled.

Relative sha1's for the paranoid:

Bundled Iris : 44535C46D474002021DE64398EBF022FF17343D4
file : iris-1.7.0-snapshotmc1.20.4-7fcec4d.jar
Sourced from This Message

Bundled DHv2 : C0745788A759A66F4AFD942FDA5892D2CD014F77
File : mods/DistantHorizons-fabric-2.0.3-a-dev-1.20.4.jar
Sourced from Job #6501066977

DH+I Nightly