Active ratting in a battleship can get you up around 90ml isk /h from ticks alone on a very steady basis. This is not including looting with MTUs + faction spawns (and faction loot).

After that the natural path is carrier ratting -> super carrier ratting.

Supercarrier ratting realistictly gets tou about 250ml /h minimum and 300 if you pay a bit more attention (ticks after about 10% corp tax) isk ticks. If you add 10/10 bookmarks, faction spawns, dread spawns, loot etc. or you hit around 350 - 450ml/h realisticly (this arent overstated numbers).

But it's something you typically do for an hour or two tops.

If you dont want to sub tons of accounts, it's way better than rorq mining. You spend less time doing it, it's liquid isk rather than having to deal with minerals and you need fewer accounts for it.