I had a similar experience on my first run but after reading some comments i got a better grasp on the mechanics and made a fresh start to see how it would go and that worked a lot better so it might be a slight lack of guidance by the game early on.
Party segment is definitely difficult and intended to crush you on the first loop. Lot of rng involved and i needed a lot of retries in my third loop for it to succeed. Doing some outdoor runs for increased max stamina is definitely the first issue but after some point stamina just becomes a trivial matter and everything is heavily dependant on rng dice rolls even with max stats and all perks unlocked.