I migrated from a mix of proxmox, hyper-V, bare metal, and Synology hosted docker onto a full k8s cluster.
It is much easier to manage now, including adding or replacing nodes. Including a rebuild of the cluster from 7 rpis onto 7 elite desk mini PCs. (From arm to x86 and from Debian to Talos)
But it wasn't a small process either.
You'll have to deploy your k8s cluster, learn how to host the services you want (using a load balancer, dns setup, cluster IPs, etc), and setting up a storage provider (I use NFS to my Synology share, not the fastest or most secure but easiest)
And then you'll need to migrate your services off the old hardware onto the cluster one by one... Which means learning docker and k8s and how they work together.
There are some things that I cannot host on the cluster like zwave2mqtt which requires a physical location centralized in my house and access to a USB zwave adapter. So even then not quite 100% ended up on the cluster, it runs on docker on an rpi though. (Technically you can do this if you pin the container to a single host and pass through the USB device, but I didn't see a reason for it.)
But, service upgrades, adding new services now that I'm used to it is very easy... Expanding compute is also pretty easy. So maintenance has gone down a bunch. But it was also a decent amount of work and learning to get there.
K8s is relatively specialized knowledge compared to the general computer literate population that knows how computers generally work... So in terms of someone being able to take over your work, if they already know k8s, then it would be reasonably easy. If they don't but are savvy enough to learn it would take a bit but not be too bad. If someone doesn't already know their way around Linux and a terminal, it would probably not be possible for them to pick it up in a reasonable amount of time though.