I've done alright on UC as a lone parent who is fortunate enough to be in full-time work. My UC works for me because a) I am left alone by the work coaches and b) the taper rate moving down in Dec 2021 was a massive help.
That is when UC works - when you are in full-time work.
I think the improvements needed to the social security system as a whole come down to:
1. dropping sanctions. There is no real evidence that these work and they just hurt people affected by them;
2. Incentivise people back in to work by increasing rates, and increasing rates when in work - UC benefit rates are still woefully short compared to 10+ years ago. The LHA has not moved in the last 3yrs. If people felt their ability to pay their rent was more secure even when returning to work, they would.
3. Change the perception of the social security system. Make the benefit system more like how the NHS is seen - as a help, not a stick to beat people with. Practical effects would be open up the DWP to doing proper benefit checks so people could feel they trust what the DWP say about returning to work. Simplify the system so people can easily see the benefits of working. Stop hassling people who are ill or carers or old or young. Teach more about the benefits system at school. I think this would take a longer time to shift people's opinions but I have known the benefit system since the late 90s and never once are the good things it does shouted out loud.