I've only played 2 tournaments which were 5USC and 5 Digit Touhou Cup (5THC). For 5USC, the tournament let a Canadian deranker in who was absolutely crazy (keep in mind it's a UNITED STATES Cup), and 5THC I could hardly play due to router problems; I also had router problems for 5USC, but I could still play for the most part.
My performance in both was alright, but derankers are absolutely crazy in tournaments, I've seen people play in a 5 digit tournament and then skyrocket to top 5k. I'd probably have a better chance getting a 500PP nomod play than actually getting a tournament badge or banner.
13th-16th place for 5USC, way higher than every thought the team would get
Didn't win a match, but losers we went 5-6 and could've won if my router was messed up (we were shocked we made quals)
In conclusion... tournaments are hard (5THC had some of the worst map pools I've ever seen in a tournament)