Having lots of job vacancies doesn't necessarily help those who're unemployed.
For example, there are around 100,000 vacancies for lorry drivers but it takes around 9 months (and quite a bit of capital) to train to be a lorry driver. Such job vacancies are also not likely to be of use to single mothers who need work that fits in with school hours.
Similarly, while there are loads of job vacancies in the hospitality sector, many of them are for skilled and qualified staff, such as chefs. Those vacancies that are for unskilled/semi-skilled staff, such as bar work and front of house restaurant staff often involve working unsocial hours. Once again, those vacancies won't help unemployed people with childcare responsibilities. Neither will they help people who'd be happy to do the work but who simply can't get to where the vacancies are because (as is the case around here) there are no bus services after 6pm.
There are plenty of jobs going in the care industry but many of them involve travelling between clients' homes (which requires a car), are in care homes in rural locations (again only accessible by car) and/or involve working evening or night shifts (which are of no use to those with childcare facilities).
Many food production factories (such as the many chicken processing plants around here in East Anglia) need staff but such factories are often in rural locations (with no public transport) and/or require staff who're able to work nightshifts. That severely limits the number of people who're able to apply for such work.
Other fields where there are lots of vacancies, such as nursing and IT, require relevant university degrees and experience. For a single mother, for example, who used to have a job (based around school hours) in the travel industry, there will be hardly any vacancies that she can apply for (and, when she does apply, she'll have lots of competition from others in similar positions).
Unemployment is bound to rise as furlough comes to an end, not because there aren't enough jobs but because there aren't enough of the right sort of jobs.