It's been a while, but I needed to reinstall my laptop again, this time under Debian Bullseye (alpha2) and Crossover 19.0.1.
I installed the game using the crosstie and the latest version of the game installer (http://live.lotro.com/sites/clientdl/lotro/lotrolive.exe).
I hit a couple of snags. Firstly, the Akamai NetSession Interface failed to download (I don't think that it's used anymore), so I just skipped it. This does not appear to have any effect on the downloading of the game content. Secondly, it initially crashed between the login screen and the character selection screen. A quick check of the debug logs suggested an issue with openal32.dll with the solution found over at https://www.codeweavers.com/compatibility/crossover/tips/dungeons-and-dragons-online/client-crashing-just-before-character-selection-screen.
It now appears to be running fine, although I've not tried the store, which is the usual bit that fails. Not that I use it that often, as I play infrequently.