Welcome to the forum, but be aware that non-EU nationals come last in the jobs queue. Employers have to prove they can't find a Swiss/EU national who can do the job. The hiring criteria is here: https://www.sem.admin.ch/sem/en/home...zulassung.html
Also the Swiss are looking to cut back on immigration from the EU too so that may or may not affect non-EU nationals.
Plus as an American citizen you should know that you're required under US law to file US tax returns no matter where you live in the world and could also owe the US tax on top of your Swiss ones. Start your research on that here: https://www.irs.gov/Individuals/Inte...-Aliens-Abroad
To open a bank account here you will be required to sign a W-9 form to allow the bank to pass the account info on to the IRS. And if any "foreign", i.e. outside of US, bank account/s comes to more than the aggregate figure of $10,000 at any time of the year you'll also need to file a FBAR form detailing those accounts and the amounts in them.
The concubine permit may be possible, but your girlfriend would have to agree to be financially responsible for you for 5 years and I don't know if you could work with that permit. Also not all cantons have this permit as the Swiss don't really do unmarried hetrosexual couples.