如果我理解正确的话，我认为你得到的数据是这样的：

fetch("https://ringen.liga-db.de/api/AllSeasons", {
method: "GET",
headers: { Accept: "application/json", "Content-Type": "application/json" },
}).then(r => r.json()).then(console.log);
// [{"Season":1999},{"Season":2000},{"Season":2001},{"Season":2002},{"Season":2003},{"Season":2004},{"Season":2005},{"Season":2006},{"Season":2007},{"Season":2008},{"Season":2009},{"Season":2010},{"Season":2011},{"Season":2012},{"Season":2013},{"Season":2014},{"Season":2015},{"Season":2016},{"Season":2017},{"Season":2018},{"Season":2019},{"Season":2020},{"Season":2021},{"Season":2022},{"Season":2023}]

每个端点将只提供一小部分数据，就像您在数据库中的一个单一表中查询一样。我认为你需要得到，例如，所有季节。然后，创建一个重复结构，并使用每个季节来获取更多数据。
就像这样：

fetch("https://ringen.liga-db.de/api/Regions?season=2000", {
method: "GET",
headers: { Accept: "application/json", "Content-Type": "application/json" },
}).then(r => r.json()).then(console.log);
// [{"RegionID":3,"RegionName":"Deutscher Ringer-Bund","RegionNameShort":"Bundesligen","RegionCode":"DRB","SortIndex":5},{"RegionID":2,"RegionName":"Baden-Württemberg (ARGE)","RegionNameShort":"Regionalliga BW","RegionCode":"BW","SortIndex":10},{"RegionID":10,"RegionName":"Südbaden","RegionNameShort":"Südbaden","RegionCode":"SBD","SortIndex":30},{"RegionID":13,"RegionName":"Südbaden Bezirk II (Breisgau-Ortenau)","RegionNameShort":"SBD Bezirk II","RegionCode":"SBDII","SortIndex":32},{"RegionID":12,"RegionName":"Südbaden Bezirk III (Oberrhein)","RegionNameShort":"SBD Bezirk III","RegionCode":"SBD3","SortIndex":33}]

当然，minimal, reproducible example可以帮助您了解您正在尝试实现的目标以及您正在使用的端点。所以，下次尽量提供它=）;