Echoes farm

Looking for the best way to grind echoes, i beat rom and im at level 49, i beat everyone before as well and i dont have online mode, appreciate any help Edit: i forgot i also beat celestial emmissary if that opens up more areas and i have +7 axe as my main, any recommendations for weapons help as well as i have most able to be purchasable and able to be used and i have the forst moon rune if there are more to bu unlocked Edit 2: im at mergos house if that helps