Is getting a new job at 40 almost impossible?

I have heard someone start at 50 and got a job in IY

No, there are Staff Engineer, Principal Engineer, Solutions Architect, Enterprise Architect, Engineering Manager, Program Manager etc. kind of roles available for 40+ year old software professionals.

But you have to study and skill up to be able to crack the interviews for those senior roles.

If you only have developer level skills after 40, then it's going to be hard to find full time jobs for developer roles. But you can still always continue to work as a contractor / freelance developer at any age.