So, finally had it, around three weeks after getting the booster.
First day: moderate fever in the evening.
Second day: a bit of fatigue (but completely functional and able to work), throat ache.
Third day: same as second
Fourth day: throat ache
Fifth day: very mild throat ache
Sixth/seventh/eighth day: nothing at all.
In general, it was as severe as a mild cold, likely less than flu.
I assume that a lot of this was because of the vaccine and I had pretty high protection. My fiancee who had covid a year before and was double vaxed, had similar experience. My two brothers (double vaxed but no booster and no covid experience before) had it much worse.
Moral of the story: get the fecking booster. We are all gonna get omicron, probably several times, be prepared for it and get the booster(s) to maximize your chances of doing well and converting a potentially. very bad experience into a very mild one.