Features I miss from chromium

Hi, I recently switched to Firefox from Edge on Windows 11, and I'm quite happy about it. However, there are a couple of - very simple - things I miss. I was able to find some "old" (2022-2023) discussions about these topics but I wanted to know if there is any news or new workaround.

• Temporary downloads: when I choose "open" after downloading a file, I would expect it to be saved in a temporary folder. I expected wrong. To me it doesn't make much sense that they're still saved in the default Download folder (or at least, give the option). For now I tried to set the default folder from the settings to the %temp% one and it looks like the "save as" option remembers the last folder I choose (the Download folder), so it should be the behavior I want. Is it the correct solution? Is there any drawback or better solution?
• PWA support: there's no option to "install website as an app". I find it very useful and it's a shame that - from what I understood - they removed it. I found the extension https://addons.mozilla.org/it/firefox/addon/pwas-for-firefox/ but I'm quite paranoid about extensions, expecially those that are "not actively monitored by Mozilla" so I wanted to know if it's safe and works, or if you found any other workaround.

Feel free to answer even to only one of the two topics. Thank you.