Nothing is stopping existing owners from downloading the offline installer backups, but existing owners will still have access to their games through GOG regardless. Delisting just means that the games will no longer be purchasable, so if there’s a game you want to “own”, as long as you buy it before it’s delisted, it will remain accessible to you for the foreseeable future.

I never got too deep into it, but I enjoyed ~10 hours of it before getting distracted by other games. It felt more like a park business simulator like Roller Coaster Tycoon, rather than an elaborate park and ride designer like Planet Coaster.

It’s totally worth $15 if you want to scratch that itch.

There’s a fantastic LotR total conversion mod for TW: Rome. It was also ported to RW: Rome Remastered, so very easy to play even on modern hardware.

EDIT: Search for Lord of the Rings: Total War (Remastered) for the most recent version of the mod.