Alsamixer has a curses ui and can be used, set the audio to the desired level and enter 'sudo alsactl store' to save your audio levels. This affects all your input and outputs so adjust your speakers volume there then save it along with your mic.
I'll stick with alsa almost purely for the mixer. Such a handy and slick little tool.
Regarding the second point: applications change it. It's really annoying. I think Discord and Zoom both do it.
If you're using pulse you can use a cli called pactl to manipulate your audio devices pretty much however you want
You can also use it to change your current audio device which is one of the major sticking points for not going back to windows for me, hitting a button on my keyboard to toggle between speaker and headphones is unbelievably satisfying
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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
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