Your questions is more related to dockerizing then actual Kubernetes (Kubernetes “just” orchastrates your containers - if they can run locally - they can 99,999% run in Kubernetes).
Spend some time learning the basics of docker - before you actually go with Kubernetes or similar - it makes better sense to know what you are orchestrating.
Get a proof of concept running on any Linux/Mac machine - or maybe even docker for Windows on your laptop - then you can see it working - and then you can start making it work in Kubernetes (deploy it).
The amount of traffic isn’t really an argument to run Kubernetes. Kubernetes imo is good if you need a lot of images/containers running.
If you only have frontend and backend - this might as well run on one or more Compute instances or even cloud run/App Engine - depending on the redundancy you need.
Kubernetes is nice - but it also comes with some overhead.
I recently started working with GCP (many years working with other stuff - Linux/AWS/Nomad/Docker etc.) and finished the Cloud Associate Exam this thursday.
I have taken the course “Architecting with Compute Engine” on coursera.org.
Its pretty trivial - but has a lot of good exercises, labs and information - and will give you some different ideas on how you can run your Application.