Just a thought, but on another forum where I moderate, we had two members who habitually experienced slow-loading or connection failure for our website after we did an update... but apparently not for other websites.
The problem was not their devices or browser software, but the age of their Wi-Fi routers. Older routers may only support slower standards, limiting your connection speed, even if your device is capable of handling faster standards via the latest protocols.
This kind of problem is particularly apparent on websites that have been updated to the latest protocols, or which require higher levels of bandwidth.