I am kind of surprised how many sites seem to want/need this. I get the slow git pages problem for some of the git servers that are super deep, lack caches, serve off slow disks, etc.
Unesco surprised me some, the sub-site in question is pretty big, it has thousands of documents of content, but the content is static - this should be trivial to serve, so what's going on? Well it looks like it's a poorly deployed Wordpress on top of Apache, with no caching enabled, no content compression, no HTTP 2/3. It would likely be fairly easy to get this serving super cheap on a very small machine, but of course doing so requires some expertise, and expertise still isn't cheap.
Sure you could ask an LLM, but they still aren't good at helping when you have no clue what to ask - if you don't even really know the site is slower than it should be, why would you even ask? You'd just hear about things getting crushed and reach for the furry defender.