In Teamfight Tactics the number of items you get from a creep round are very random. I have completed the first 3 creep waves and got 3 or 4 items, while a run later I did not get a single item from those 3 rounds. I think everybody should get 1 random item from each round or the odds of getting 1 item should be a lot bigger. Like 80% to get one item, 10% to get nothing, 10% to get two. (Percentages are random just for the example).
With the items being more powerful than champion synergy (in my opinion), your odds of winning after being 3 items behind early are very low (vs decent players).