Docker by itself is not a good thing, bad with security, not entirely open source, buggy networking, not very reproducible
The problem with docker was timeout for requests, not sure whose falt it was, but the reverse proxy container was unresponsive pretty often
Also, yeah, RPI was not really fast too, it had 8gb ram, boot from ssd Just right now I have i9 with 64gb ram, and this is stupid fast, and actually for most of the apps the performance bump is like 50%
About docker, really, try to look into nixos, it has a really steep learning curve, but it will worth it, and you will be able to do magic