If you hate Thalmor like any sensible Skyrim player, here's a mod for you: Assault on Valenwood will end the treaty between the High Elven Supremacists and the Empire, allowing you to join the Imperial Legion in the war over the province of Valenwood. You will be supported by the local Wood Elves and Khajiit as you retake the province one city at a time.

Based on the previous Valenwood mod, this mod adds combat over a vast map. Note that the original mod is not required to use this mod, but Skyrim Special Edition version 1.5.73 or higher and, as the mod creator theblackfist warns, "many squires to help you and your allies" and "many potions" are needed.

To start Assault on Valenwood, go to the docks in Solitude and find a ship called the Avenger. Find and open the trap door on the ship and enjoy your time in the Imperial Navy.

Here are the best mods for Skyrim Special Edition.