MassiveBonk51

I have 4 years of experience doing microservices using spring boot, Kafka etc at a large financial institution. However I'm running into trouble when I try to apply for jobs. Everyone wants experience with containerization and public cloud. I basically never got a chance to do this at my job since everything is hosted on-premises using VMware's Cloud Foundry. I have been working on learning all this stuff but I just keep getting rejected because I don't fit this checkbox professionally and it feels like I wasted 4 years. Where do I go from here?