How can I make KDE respect my choices for download location
I use different browsers to do different tasks, but downloading a file/image goes where ever location I used last, ignoring what I set my browsers download location to be
For me I have no problem with this in KDE? Different browsers behave differently.
For me Firefox either saves to last location used or a set directory depending on user settings. In about:config you can see browser.download.lastDir which is how this is done. KDE is not driving this, Firefox drives it. I do find that set up a bit annoying to be honest, but I like seeing the dialogue box each time rather than everything going into downloads folder.
Chromium based browsers do it slightly differently, I think it's per website if you don't set it to a specific folder. Vivalidi seems to work that way for me anyway.
In my experience firefox also seems to remember where I last saved something from each website, and by default opens the download location dialogue there so I can often just hit "save".
If I'm saving something from pixiv, it goes to where I last saved something from pixiv. Same for imgur, catbox... Etc.