I had the original and it just felt like a very strong hit of bronchitis. Was enough to knock me on my ass hard for a week, and then a few months of feeling something was still a little off (my taste buds changing was the most notable). It was certainly a doozy.

The two subsequent times I got it within the same year (job where I traveled and met a lot of people) I barely even registered I had it other than coughing a little more and wouldn't have even gotten tested if not by force from work policies.

It was always going to be extremely bad at the outset, that's just how new viruses work, but their attempts to "prevent" it were always going to fail because you can't stomp it out once it breaches containment. You just ride the wave until that immunity spreads enough to render it endemic.