I’m facing the same problem!
Club Tournament 3 rounds only

I’m facing the same problem!
This is old, but you have to have at least half as many players as the number of rounds when the event starts. So, if you want 7 rounds, you'll need at least 14 players.
It will cut the rounds to half the players, rounded down otherwise, and I believe you have to have at least 5 players, but it might be 4 now. In that latter case it may allow three rounds, but I'm not positive.
Thank you a lot, Martin!
I've received an answer from the chess.com support sharing the same:
"For Swiss Tournaments:
There is a maximum amount of rounds in Swiss tournament limit which equals to: (the number of players) divided by 2, rounded down. For example 15 players max 7 rounds.
2 players -> 1 round
3 -> 2
4 -> 2
5 -> 3
6 -> 3
7 -> 3
8 -> 4
9 -> 4
10 -> 5
11 -> 5
12 -> 6
13 -> 6
Every player will play every round, and the player with the highest number of points at the end of the tournament is the winner. In a Swiss tournament, you don't necessarily play every other player. If there are a lot of players in the tournament, there may not be enough rounds for everyone to play everyone. Pairings try to put together players of similar ratings. Because of this, the highest-rated player might not always be the winner, and a lower-rated player who beat all his opponents (who would be of similar rating to him) could end up winning."
It seems improving the UX around creating tournaments is a good idea!
Hi guys, I have recently set up a couple of blitz tournaments for our club members, and no matter how many rounds I put in, eg 10, when the games start, the rounds reset to 3. Eg round 1 of 3....
The amount of players has varied up to 8 or 9 members. Has anyone seen this? I have set up tournaments before where this didnt happen. (I'd much prefer to be able to set up an arena tournament but I dont think this is possible)