This is going to probably bump this which is not my intention, but I saw your question while I was at work and wanted to answer it for you.
Between Total Warhamer I and II I have around 600 hours played.
Its a game that is more interesting if you know more of the lore, because the factions in game play like they are lore wise. So if you like certain factions some are made into DLC. Some of the DLC are $20 while some are $8-5.
Base TTWH1 gives Empire, Dwarves, Brettonia, Vampire Counts, and Greenskins
Base TTWH 2 gives High Elves, Dark Elves, Skaven, and Lizardmen
DLC: Chaos, Wood Elves, Beastmen, Norsca, Tomb Kings, and Vampire Coast
Edit: They have massive amount of FLC (free dlc) in terms of lords and factions like chaos/norsca were free when they were released initially.
I’m a huge chaos fan so I forked out the money for that, but say if you don’t like beastmen you don’t have to buy them and the game still plays the same. They are all worth it and you can wait for when they go on sale which is what I did for Wood Elves.
There are multiple difficulties and lots of min maxing potential with how you play because you design your army compositions and fight the battles. You can have all elite troops but if you command them poorly like how you setup your artillery or if you leave your shock cav (lances+charge) in melee too long you’ll loose. You also have to mange provinces on the map and construct buildings during “turns” so its not real time until you fight the battles.
Equating it to LOTR is not the best because Warhammer evil factions are much stronger, and its “grim dark” which equates to the forces of good are not always destined to win. For instance; the empire/dwarves literally have gunpowder and build football field tall walls to keep out chaos (all melee army) and its not enough most of the time. Often you don’t start in an advantageous position which is part of the fun using diplomacy or your armies to unite forces.
The scale of the map in TTW2 for campaign is like a guaranteed 200 hour play through if you commit to conquering everything (IE woodelves can occupy any settlement playthrough). That whole 200 hours some faction is always going to be strong enough to challenge you because your armies are spread out fighting multiple threats that require you to manually fight your battles so you don’t lose too many soldiers.
Each individual race has its own mechanics in campaign so no play through is ever the same. Its good fun. Stellaris is good RTS too if you’re looking for another.