The answer: treat every fight as a recorded lineup from the same numbered day, not a live duel. The rule is one sentence - same-day saved board, take as long as you want in shop.

1What Happens When You Hit Battle

2What Changes Because It Is Snapshot PvP

Shop habits
Spend time in shop, not in panic Battle
Live-PvP habits lose runs here - day 5+ losses cost 3 lives. Rushing because "someone is waiting" is how players bleed out on one sloppy lineup.
Building
Build for the day you are on, not for "who queued"
Snapshots come pre-committed to a core (Formiqueen commons, Berroon items, Plunderbird water). You cannot outplay them mid-fight - only out-shop them first.
Rematches
No revenge games
Matchmaking avoids facing the same board twice in a run. Your board can still be served to other people later as their opponent snapshot.
Ranked
Stars come from your finished run
You are not beating a live player climbing at the same second. Climbing means beating today's boards.
Extended / endless is the same system with a nastier pool. After a 10-win, enabling Extended in Settings shows unsoftened snapshots - still nobody is live. Players pushing day 20-40 describe every late lobby as another saved monster board.

3How to Play Around Snapshots

Common Mistakes

Bottom line: same-day saved board, take as long as you want in shop. If search feels empty, that is pool size, not a missing live queue.