The Horizon feels real is a Modpack built on making Distant Horizons, a mod that loads more chunks whit less lag using LOD's, Prettier and Faster, It uses many Optimization mods and QoL mods, it also use some Cool mods like the Chat Heads mod.
This modpack utilizes Cave Dust, First-Person Model, Iris-Shaders whit BSL and Complementary Shaders - Reimagined already included, Sodium, Drip Sounds, Lamb Dynamic Lights, Saiko's Tools and Swords and much more to Optimize your Experience!
As you can see in the Picture, in normal Minecraft 1.19.4 I get 117 FPS whit a Low FoV, in my Modpack on 1.19.4 though, I get 180 FPS whit 200 FoV, this is because my Modpack uses various Top Notch optimization Mods.
Distant Horizons shows more chunks using LOD's.