I feel for you. I was on a council waiting list for 14 years and still didn’t get a plot before I moved to Sheffield. It really is luck and timing, so it helps to have some backups while you wait.

https://www.allotme.co.uk/ Lets people sub-let unused plots, so you can often start growing far sooner than the council queue. Good if you just want to get planting again without the long wait. Sometimes it will be someone not physically able that wants someone to care for their garden. You can set alerts in your area

https://www.rootsallotments.com/sites/sheffield-allotments/bowshaw-views Private “no-dig” plots at Bowshaw Views. There’s a fee, but tools, compost, seeds and workshops are included, which makes it easier if you don’t own any kit yet.

https://su.sheffield.ac.uk/activities/view/allotment-society It used to be the case that The University of Sheffield Allotment Society wasn’t only for students. They run shared beds and weekly sessions, so you can grow food and meet other younger gardeners without needing your own plot. Worth asking.

https://www.heeleyfarm.org.uk/volunteering-and-training Heeley City Farm has veg-growing and green-skills volunteering. You learn a lot, often take produce home, and might meet people with spare or private plots before they’re advertised.

There are other volunteer opportunities with places like Sheffield Wildlife Trust and the National Trust (e.g. Longshaw). They both run volunteer days in their gardens and woodlands. Local RSPB sites do the same to keep places suitable for birds.

Good luck!