sodium problems
I'm using iris, sodium, DH and tectonic as my main mods and couple of other optimization mods (all for 1.21) but i found that the newest version of sodium 6.0.0 with the newest versions of other main mods gives notesably worse performance than previos versions (sodium 5.11, DH 2.1.2, iris 1.7.3). theres also a problem where shaders wont load if i have DH enabled, so i have to disable DH, enable the shaders and enable DH again. i am using amd cpu and gpu and i'm playing fabric 1.21.
Solution
you have another mod changing the max render distance. Bobby does that but I don't know why you'd want to increase it if you're already using Distant Horizons, which by default gets you 128 chunks of LODs for less of a performance impact than something like 48 chunks of normal render distance without DH
