hello, i am affraid you might not like the most obvious answer, which is just to keep digging them out, making sure you get all the root out. if you don't fancy this there are a number of chemical products on the market that are safe to use in the garden.

if you decide to use chemicals then as they develop into active growth in early summer. and i find a dose just before they go dormant often concentrates the posion in the plant and kills it off over winter.

a christmas mesage to all new gardners who are trubled with weeds hoe hoe hoe, and keep it sharp.

I know that there are question marks about glyphosate as it doesn't degrade the moment it touches the soil, as claimed. But even so, I don't think there is any alternative to getting out deep rooted weeds like thistles, docks, and bindweed. (Apart from digging all the way down and getting out every fragment of root..difficult on heavy clay or if the weeds are in a densely packed flowerbed.)
But you can save money and be environmental at the same time by not spraying glyphosate everywhere, and instead contact weeding, touching the leaves of the nuisance plant only with a sponge or 'wand'. I doubt very much weedkiller even enters the soil in this way. An old lady I once knew eliminated bindweed from her rockery by tucking the growing stems into a jam jar full of glyphosate solution, which she moved from weed to weed each day.
The much vaunted 'alternative' of covering the soil with carpet, black plastic, or whatever for a year, just doesn't work in my experience, as the worst of these weeds come back from fragments of root which have survived without light for all that time.