Edition Patch 1.5.97: Unofficial Skyrim Special

Installing the correct version requires a deliberate process. You cannot simply download the latest USSEP from Nexus Mods, as that will be for AE. Here is the step-by-step guide.

AE forces you to download four free Creation Club mods (Survival, Saints & Seducers, etc.). The USSEP for AE includes hundreds of patches for these CC mods. If you don't want those mods, the AE USSEP will still check for them, leading to errors. The USSEP 1.5.97 is lean. It fixes the base game and nothing else. Unofficial Skyrim Special Edition Patch 1.5.97

Veteran modders know exactly what works with 1.5.97. There are no surprises, no “monthly Bethesda update breaks all my DLLs” headaches. Installing the correct version requires a deliberate process

Eventually, yes. Mod authors are slowly ceasing support for 1.5.97. The revolutionary Community Shaders works on both versions, but new animation frameworks like Open Animation Replacer work better on AE. Eventually, yes

However, for the "Legacy Mod Build"—the 3000+ mod list that took you two years to curate—USSEP 1.5.97 is immortal. As long as people play Skyrim on PC and despise forced updates, version 1.5.97 will have a community.