A venue model independent from a team's free-text "stadium" field: it defines courts or fields per competition, with opening hours and duration.
Address autocomplete
Via OpenStreetMap Nominatim, free and with no need for a paid API key.
Schedule conflict warning
The calendar warns if two matches clash at the same venue — it doesn't auto-generate the schedule avoiding this, but it does flag the clash so the organizer can resolve it by hand.