Don't think too much. People in Bangalore and Hyderabad are changing jobs often and it doesn't bother companies, not sure what is the mindset of the companies in your city.
Its not red flag unless you have changed 5 companies in 5 years. Start looking for a better job.
Also, it seems companies somehow are able to access salary account credits, if they spot any other regular income, they are firing the employees. That is many IT companies here in India fired lot of moonlighting employees.
If you company is small, then chances of happening this is less, you can take the risk. Check the sites mentioned on above comment and search online forums like reddit to find out which sites are reliable and protect freelancers from getting scammed.
This is my 4th company. Left first & third company for similar reasons (layoff due to financial issues in the company, third one to prevent layoff to be precise)
I don't have a separate salary account by the company. In current company, salary is credited in my personal bank account
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