Yeah I feel like anything with random outcomes is always going to roll a bunch of 1s at some point! I assume a lot of games use some sort of pseudo-random thingo like Dota does https://dota2.fandom.com/wiki/Random_Distribution. Which I guess is kind of what you’ve done there with the 20%, so I just got quite unlucky! Potentially you need to bump up the % faster in later levels or something like that? In this case if you get to turn 6 before you get a starter you’re basically dead without a chance to play anything?
No idea about testing, but that would be a fun problem to play around with.