I used to run HA on an RPi, but eventually migrated it to a similar NUC. The RPi eventually just wasn't powerful enough (peak compute needs), while the NUCs are still quite cheap. And you can run a surprising amount of Proxmox VMs and LXCs on barely a few cores and gigabytes of RAM.
Wow, not sure how to interpret your experience that a RPi wasn't powerful enough to manage watering a few plants. I can only suspect the overall software setup is massively bloated.
I use an RPi 4 w/ 4GB of RAM and a 1TB usb 3.2 SSD and it flies through all my workloads. Though I don’t do any video encoding things.