I'm a left-handed mouse user, but decided after 20 years to switch because this game is essentially forcing me.
However, when I remap WASD to ESDF, the key map screen shows the old WASD mappings after I reload my game. The ESDF still work, the displayed mappings are just wrong. In some cases, this led me to have 1 binding for 2 actions.
The only way I could be sure to get the mappings right was first to reset to defaults, then map everything in one go. This managed to get my mappings right, but next time I load the game the mappings are displayed incorrectly.
This is unrelated