Update: LOTRO + WINE: Strafing with camera?
About two weeks ago, I submitted a question concerning some lost inputs I was struggling with when playing LOTRO (that post can be found here). Since then, I've tried reconfiguring WINE, checking for system keybinds and short cut interference, changing the DX version of the game, going over hardware, and testing a few dozen other games installed via Steam and run using Proton compatibility tools to try to figure out what was going wrong. Today, I finally tried uninstalling LOTRO and reinstalling it on Steam and found that the problem I was having stopped. For anyone looking for explanations and remedies of a similar issue, I'm sorry to say that I couldn't get to the root of the problem, but running the game through Steam to use Proton did fix my problem.
The gist of the issue was that while playing on Linux (specifically a nearly fresh installation of Ubuntu 26.04 LTS), making too many simultaneous or near simultaneous inputs would lead to losing some of those inputs, and I wasn't able to predict those loses reliably. An example I used there was if I attempted to walk forward with W, strafe with E, and turn my character and camera by right-clicking and dragging, making the inputs too fast would result in a diagonal walk with no turn, forward walk with turn, or strafe with turn most of the time. This was annoying while playing landscape and leveling, but I think it would have really frustrated me and fellowships if I couldn't reliably move during encounters, so I sought to fix it.
Thank you to everyone who responded in that fist post. I feel like even if I didn't fix it directly through editing and tweaking the game, WINE and the OS, I learned a lot about my new OS, the tools available to me, and the options I have to really customize my computer.