Over time you will come to realize that your boss is not a good manager. Right now, she seems wonderful, but then everything you hate about your job is a direct result of her poor management skills.
Any manager worth their salary would realize that you are a single point of failure in the system, and would do everything in their power to mitigate that weakness. Cross-training. Bringing in interns to help out with the mundane stuff, so you can focus on doing the things that only YOU can do.
She is about to have a reckoning with her management, as to why her team of 7 is now down to 3, and key - possibly irreplaceable - skills have been allowed to walk out the door, and nobody has been cross-trained to fill in the gap. What if you had gotten COVID? Or slipped in the shower and broke you ankle and couldn't come in? Etc.
A good manager makes sure your work gets done, regardless of the name on the work. Because if the answer to ANY question is a person's name, then that person's manager has failed.
She will learn from this experience. She will become a better manager. And you will be better managed in the future. You have done right by everyone. You can rest easy. And move on.
As for moving far away...
I've moved overseas twice, lived in two different states, four different countries, and have Learned How To Move.
First off... bring NOTHING. Seriously. Everything you think is important right now, won't be important in your new arrangement. And, if it is, you can always have it shipped to you or buy a new one at your new location.
Second... immediately get out into the area and interact with the locals. Coffee shops. Butcher shop. Farmer's market. Whatever. THAT is where you will find your groove, figure out how to fit in, and embrace the local culture.
I mean... that's why you are there is in the first place, right? Not to export your old life to your new location, but to embrace the new everything in the new place! So do it! Leave the past behind and move forward. You can go back and get the important things later.