You don't have to do it all manually. Tools like LOOT (Load Order Optimisation Tool) can automatically sort your mods based on a massive community database of known conflicts.
Many popular mods have community-made "compatibility patches" designed to make them work together. Order Mods
If your load order is wrong, a small bug fix might be accidentally overwritten by a massive overhaul, causing glitches or broken quests. You don't have to do it all manually
If you can't find the culprit, disable half your mods. If the game works, the problem is in the other half. Repeat until you find the specific mod causing the conflict. Order Mods