I had COVID as well, and it absolutely floored me. I have no underlying medical conditions, and have always been fit, not overweight, no family history of heart disease etc etc.
I wasn't sniffly or coughing. I had severe indigestion type pain (like intense cramping) and significant breathing difficulties, fatigue and extreme lathargy. Water felt like literal pins everytime I showered. I was over it within 5 days, but it was absolutely intense. If the difference between your symptoms and mine came down to viral load at the point of infection, then there's no anticipating how one person might react compared to another.
I had gone into work the day I fell sick, and I was sitting next to our lead investigator who was like 100 years old. He didn't get sick, and I sat next to him all day literally wondering wtf was happening because my symptoms were not what I was expecting for COVID. My partner caught it, and she had the same symptoms as me but was able to function pretty normally.
The person I caught it from, literally a 29 year old fit person, was in hospital on a ventilator the week before.
Again, your experience is one others had, just as mine was an experience others had.