A studio is a company that makes games. They don't buy games from outsiders, generally. What you are looking for may be a publisher.
If a publisher is looking for submissions, they are going to tell you how to reach out. Example: https://www.team17.com/pitch-your-game
The answers to questions 3 and 4 are, of course, "it depends".
I might do it in the future if, and only if, I have a game in whose market appeal I am reasonably confident. Publishers are unlikely to be interested in something as aggressively unmonetizable and unmarketable as Collared Maid, but that might be different for future projects. I'd also need to have confidence in my ability to actually deliver a finished project on a fixed deadline, which for this project I do not have due to my job and various personal circumstances.