I browsed to my jellyfin media library with the network tab open and set the filter to "Played" and it made a request like this:
https://{ host }/Users/{ user_id }/Items?SortBy=DateCreated%2CSortName%2CProductionYear&SortOrder=Descending&IncludeItemTypes=Movie&Recursive=true&Fields=PrimaryImageAspectRatio%2CMediaSourceCount%2CBasicSyncInfo&ImageTypeLimit=1&EnableImageTypes=Primary%2CBackdrop%2CBanner%2CThumb&StartIndex=0&Limit=100&Filters=IsPlayed