Are there easily available options for scientists in foreign countries if they don't find suitable job in home country.

Most scientific jobs require qualified and dedicated professionals, whether that be in academia or the industry. Hiring the right talent is always a priority over geographical borders. I can speak for a few countries in Western Europe where I have experience in both trying to get hired and later hiring, and here we often see shortage of talent. Of course, policies are sometimes in place that can slow down hiring talent from abroad (depending where), but I can tell that if there is a profile and personality match, hiring managers will go through cumbersome administration to secure it, if possible.

easily if you are excellent in your field with proven scientific work and impacts. if not then generally they would accept local than foreigners. or maybe if your field is required in the target country and there are fewer applicants applying.