It may be easier to do a thorough job to knock the pot off (pick it up by the trunk base and sharply smack the rim of the pot) and comb off the top of the 'ball'. Then, simply set it back into the pot and replace the bit of missing soil.
Some of these weeds will come back after you pull them. Some grow back from any roots left in the soil, others from dormant seed. You will probably need to keep weeding for a couple of years or until you do a full bare root repot.
I use glyphosate brushed onto the leaves of weeds. Kills all the roots so they can't grow back. None of my trees have been affected by brushing glyphosate onto weeds in the pots. Obviously don't brush it onto the leaves of the trees you want to keep.