I have a WMD run on Hectic and am wondering if it could be difficulty verified through the password on the intermission screen. For example, the password that will pop up on a Hectic BG completion is CDP8 9BJ2 68ZT SVK? while on WMD it would be CSNR 9BJZ 680? LVK? I’m just wondering bruvski. You can check all of the passwords on this doomwiki page, the password that will appear on the intermission screen will be for the level before it.

Edit, While writing this post, I did not realize that the passwords could be different than normal, for example I got the password CT5R 9BGZ 68H? L3K? on a run and was confused until I just put it into this decoder and learned that it gave me 50 health and not 100.

This is a good question and I hadn't thought of using that for verification, mostly using ammo gained or damage taken as our way to compare before. I think this would be a good backup way to verify a run if we're not sure!

Yes, passwords carry the meaning of your entire inventory because they need to be able to restore it throughout the entire campaign. That said, using any decoder (personally recommend the one in the Compendium) will give you the difficulty (and the full inventory for that matter) without any ambiguity.