Most cloud providers have a similar offering to AWS Lambda, plus it is not that hard to convert your code from the event handling pattern impose by AWS Lambda to a long running container running in K8s or VMs like you are doing yourself

IMO the lock-in fear is overblown as the top cloud offerings (S3, Lambdas, K8s as a service etc) are already commoditized among the top providers, the exception being specialized databases like DynamoDB, Spanner, Cosmos …

Not saying there wouldn’t be some major work to switch your operations from eg AWS to GCP, but it is also not a hard lock-in