Have you thought of woodchipping?

Place cardboard all over the weeds... then dump a few inches of woodchip... no more weeds, far less watering....

I did a large area with bad ground elder... I did take some out.. way more than I needed but it was neglected so the roots where full on... but its so much easier you wont regret it...

Lots of people on yt who can show you how effective it is as a gardening technique.. you just top up the woodchip every couple or whatever years... its fabtastic... and often you can get the woodchip free...