Create a modlet with these xpath statements modifying Config\Xui_Menu\windows.xml to add to extend the Loot respawn dropdown in the menu.
<set xpath="/windows/window[@name='newContinueGame']/rect[@name='tabs']/rect[@name='tabsContents']/rect[@tab_key='xuiGameSettingsAdvanced']/grid/gameoption[@name='LootRespawnDays']/@values">-1, 5, 7, 10, 15, 20, 30, 40, 50, 100</set>
<set xpath="/windows/window[@name='serverBrowser']/panel[@name='serverfilters']/panel[@controller='TabSelector']/rect[@name='tabsContents']/rect[@tab_key='xuiGameSettingsAdvanced']/grid/browsergameoptioncombined[@name='LootRespawnDays']/@values">-1, 5, 7, 10, 15, 20, 30, 40, 50, 100</set>
In my version I go to 300 days, for those long games.