Is HTTP the issue here though? Most of the time it seems to be more to do with the server taking ages to respond to queries. E.g. Facebook is equally poor on mobile as it is on my fibre-connected desktop (which I assume is using HTTP/3 as well) so I have my doubts that swapping HTTP versions will make a difference on mobile.
I did find it amusing how the author of the linked article says the megacorps are obsessed with improving performance (including the use of HTTP/3 to apparently help improve performance). In my experience the worst performing apps are those from the megacorps! I use Microsoft apps regularly at work and the performance is woeful even on a fibre connection using a HTTP/3 capable browser and/or their very own apps on their very own OS.
I did find it amusing how the author of the linked article says the megacorps are obsessed with improving performance (including the use of HTTP/3 to apparently help improve performance). In my experience the worst performing apps are those from the megacorps! I use Microsoft apps regularly at work and the performance is woeful even on a fibre connection using a HTTP/3 capable browser and/or their very own apps on their very own OS.