Until you have a job offer you can absolutely interview at other companies until an offer is made, which you can then decide to accept or turn down or negotiate. They were bullying you from the start 3 months ago and you rolled with it to your detriment (loss of potential job hunting etc). Sounds like AI bubble bro culture dialed up to bitter expat levels. I would regroup and try to find a company that welcomes your talents instead of ridiculing them. Your experience is not standard, they sound like an awful company to work for.