In my experience, adopting Kubernetes is seldom a well informed decision weighting the pros and the cons. Usually it's a stampede effect of higher-ups pushing for Kubernetes, because everyone else is, without really understanding what it entails.
The truth is, Kubernetes is awesome, it brings many features to the table. But it also requires ~10% additional very expensive headcount, ~20% more tasks overall, and prolongs the release cycle by ~20%. Figures are from my experience. Those drawbacks are rarely ever discussed - it's just dumped onto existing teams on top of their existing responsibilities, leading to struggle and frustration.
Speaking from personal experience, I feel like you just pulled those numbers out of thin air.
At my job, we went from overly complex Elasticbeanstalk deployments to pushing out new releases via Helm charts into k8s...deployment time vastly improved as did cognative load on what was actually happening.
Elastic Beanstalk is a halfhearted attempt at reproducing Google App Engine or Heroku. It is not comparable.
GAE, on the other hand, is dreamy compared to K8s. I once moved some infrastructure to K8s because it was costing too much on GAE; I ended up moving it back because it was worth it. We've subsequently moved it to Digital Ocean's PaaS but that's a different story...
Beanstalk, while great when it came out, is not a great solution now. It was also never really meant for teams who run things at scale. It also got quite complicated because it just didn't expose a lot of knobs.
I think you'd find ECS or similar as easy to work with as k8s and all of them will be faster than beanstalk.
Beanstalk is ALWAYS purposefully slow, this is by design. It mimics how amazon deploys internally, slow and steady wins the race to safety. It also has some really bad issue if from from a bad deploy back to a broken app; eg you can wedge it pretty bad.
Anyway at this point I don't think Beanstalk is a fair thing to compare to. It's good you moved off.
To add to that, a step to use anything from Google is a step onto Google's infamous "deprecation treadmill". A rather frustrating lifestyle (unless you are inside Google and your code gets updated/maintained in the monorepo).
The truth is, Kubernetes is awesome, it brings many features to the table. But it also requires ~10% additional very expensive headcount, ~20% more tasks overall, and prolongs the release cycle by ~20%. Figures are from my experience. Those drawbacks are rarely ever discussed - it's just dumped onto existing teams on top of their existing responsibilities, leading to struggle and frustration.