Have you discovered that by running speed tests, or just by observation?
I'd expect to see differences when downloading large files, but with web browsing there are many other factors that affect speed. I had fibre broadband for a while and only really noticed the difference when uploading photos.
Hi! The download speed will be effected by a range of factors as well as the network generation e.g. signal strength and how users there are (contention). For example you might be close to a 4G transmitter and further away from a 5G transmitter (though often will be co-located). A good app to try is Network Signal Info (KAIBITS) which provides connection details if you want to experiment more!