not about stress but to have HA proxmox cluster you will need at least 3 machines or fake one with a quorum machine without vms on it. Sure your vms will run if one machines goes down, but do you have HA Storage underneath? ganesha would work but more complexity or another network storage with more machines. Don't get me wrong it is fun to play with, but i doubt any homelab needs HA and cannot have a few minutes downtime. Or what do you do in case your internet provider goes down or when you have a power outage? i don't want to provoke, i have fiber switches and 10G at home and have 2 locations to switch in case one location goes down but i can live with multiple days of downtime if i have to, or if not i take my backups and fire some VM's on some cloudprovider and be back online in a few min and pay for it because backups are in both locations.
i would much rather develop a simple LB + autoscaling group with a deployment pipeline (lambda or some other control loop) and containers on it than a k8s cluster the client is not prepared for. if they outgrow this, most likely the following solution is better than going 100% "cloud" the first time. Most clients go from java 8 Jboss monolith to spring containers in k8s and then wonder why it is such a shitshow. but yeah pays the bills so i am not complaining that often ^^
