This work is within the scope of a garden labourer. The problem is that it can produce a lot of green waste. A large compost pile can be the most economic solution. Compost will be sped up if branches are cut down and thicker material disposed of separately.
A shredder or mulching machine is helpful and the mulch will build up your garden beds. But these machines need to be used cautiously (for your own safety including your ears, and because they are prone to damage). Note that mulching doubles the time the job will take.
For overgrown lawn, you can find a lawnmowing person who will knock is down and mow it for maybe double the normal mowing price. What annoys me is:
when a customer doesn't acknowledge how much harder it is to mow overgrown lawn
When a customer regularly lets a lawn get overgrown before calling me, mostly because they don't want to spend money (and I encourage this by doing it for the standard price because they promise they will have me mow regularly in future)
Ongoing, regular mowing is good at encouraging grass and discouraging weeds. And you can get spray that kills weeds but not grass - see how a small patch handles it before you spray the whole lawn.
The mistake I see people make with overgrown garden beds is killing or removing weeds and then failing to prevent more weeds from germinating in the earth and space left unoccupied.
And this is what really crushes a gardener - having to do a tiring job more than once.
Once weeds are dead, dying or gone, install mulch to 6" (15cm).
Cheap mulch is available from tree loppers. Nothing excites a partner like coming home and finding a mountain in the driveway.
Any concerns about the quality of this free or cheap mulch are less than the concerns of weeds returning in your garden bed.
People typically fail to put mulch on deep enough and fail to accept that reapplying mulch is an annual task.
You'll still get the odd weed come up through the mulch, but that is not too hard to deal with.