This site is going to be an effort for old browsers on slow hardware and poor internet connections.
Some people might find this interesting… the sort of thing I bet MichalG could lose a day in:
IF in chrome, use developer tools F12 to inspect all sorts of fun info.
If you do a ‘clear cache and hard reload’ then you can see all the stuff that gets loaded in the Network tab:

212 individual requests for items to draw a single page! 3Mb of transfer which is twice that when uncompressed.
An awful lot of that is javascript. All sorts of javascript needs to be parsed (to see if it needs running) and then maybe some if it needs running. Anyone on IE is going to feel pain… but not sure why anyone would still be using IE!
It is probably pretty greedy on memory as well. If you have lots windows like this open in chrome and you ‘only’ got 4 GB memory then things might start to slow down.
Pretty typical of a marketing site that is maintained by WordPress Content Management System. Incredibly inefficient.
Lots of that static content might be cached… locally at browser, and also on the web somewhere (cloudflare) to help with network speeds. So things should speed up after first page load, but javacript will still need running. Depends on detailed cache preferences/settings.
Unlikely to be server table locking.