I'm not running a very big operation, I only have two nodes which host a few custom webapps and a few dozen WP sites. Running in a single region removes the extra charge for HA GKE, letting me run pretty lean and just pay for the VM, storage and bandwidth. I hardly ever have to spend any time on managing the cluster, it keeps chugging along while I get things done and makes it easy for me to manage app lifecycles. YMMV.
I keep it simple, I tried helm but didn't like it because it added too much complexity. I pull in cert-manager and nginx-ingress to every cluster I run but nothing else. I build my images locally and push to the registry directly, no CI/CD. I focus on the core competencies of k8s and try to stay lean and conservative with adding new tools or components.
I fell in love with it because of the dev and ops experience. Just the shift of perspective from pets to cattle is a big improvement. Deploying via sftp is simple but k8s really helps me with the other aspects (monitoring, logging, scheduled tasks, TLS cert mgmt, blue/green deploys, multiple environments, etc) of managing apps that my clients use regularly and depend on. It's nice having one API platform that can handle all of this and feels more like assembling Lego blocks instead of bespoke solutions for every project.
Hope that gives you some insight!
_I_ don't have 10 engineers and thus it's the wrong tool for me and I've decided to not invest in it.