You can hire an Azure or Google Kubernetes devops guy and he will be equally comfortable on your AWS EKS kubernetes cluster. And when he leaves, you don't have a six week onboarding process with the new guy to learn all the ins and outs of your totally bespoke, non-standard container orchestration system that was cobbled together by two devs with no operations experience.
K3S takes about 5 minutes to setup the first time and you instantly have an entire universe of standardized operational tooling. I wouldn't touch docker compose with a 20 foot pole for production work.
Docker compose is hardly "totally bespoke".
Setting up K8s isn't rocket science, but maintaining it are offputting, to say the least.