Responses
I C&P my reading lists into a spreadsheet and (try to) keep it updated. That way I can keep it on multiple devices.
However, after the server crash another reader created this:
https://docs.google.com/document/d/14Drj0CviUhrAmZlU-DC-AtxGFQoH1_PYQ81b2Vzu82w/edit?tab=t.0#heading=h.acjitdw8v0h
I haven't used it. But it may fit your needs.

Does anyone know how I can save all the mangas I’m reading with like some sort of back up instead of writing them all manually into my notes app I’m scared that something is gonna happen to this website cuz I keep seeing people name dropping it