A £30k salary does not mean £2,500 appears every month. Tax, National Insurance, pension and student loan deductions all happen before rent even enters the chat.
The useful question
After deductions, rent, transport, food and bills, how much life money is left? That is what decides whether the salary feels calm, tight or weirdly disappointing.
Compare jobs by monthly disposable income, not just the salary number in the job ad.
Try salary after uni