Pretty much this. There is a significant learning curve to kubernetes (or similar, I guess?), but it’s a handy skill to be familiar with. If things basically run but with degraded performance on one raspberry, there is no real need for a vertical performance increase. Adding the second will provide almost double capacity, with some HA added for fun.
I like beer, I prefer IPAs. “bitter and boozy” is how I describe what I want to bartenders and matchmakers. You don’t like IPA, then don’t drink it?