In my opinion the site hasn't been updated to account for new variants having different symptoms and progress. I didn't have a fever cough or loss of taste or smell first couple days.
I had runny nose and very sore throat and headache - which as I'm prone to tonsillitis I was thinking it was my first bout of that this winter (I get 2 or 3 most winters), then the fever hit end of 2nd day and rather than loss of taste and smell everything remotely savoury tasted like pure salt! Not a symptom I'd heard of till it happened to me and then I learned around 1/3 of sufferers experience this. So weird!
Cough didn't arrive until day 6 and then it came with a vengeance! Making me cough so hard I couldn't catch my breath and even so hard I was gagging and vomiting! Horrible! Around this point mucus production also went into massive overdrive just insane! Went through SO Many tissues!
I'm now 3 weeks on from first symptoms and I'm still weak, tired, appetite not great, sore throat, bit of a cough still but nowhere near as bad as it was, still snotty but again not as bad.
I did a tidy up yesterday as place was a tip after 3 weeks of basically very minimal housework being done! Only a couple hours I did but it totally wiped me out! I'm
Sore all over today and totally knackered!
And that was "mild" COVID! I've very very rarely felt that bad with this kind of illness. I'm that annoying type of person that can usually still crack on if grumpily when I have tonsillitis/cold/flu.
This has utterly floored me so I really hope you're right it's not COVID.