Is it advisable to stay in the UK for 4-5 years after completing my studies to understand the job market for a Master's?

You can absolutely turn a UK Master's into a 4 to 5 year career runway, but only by treating it as an active sponsorship plan rather than a passive observation period. You will move through two separate visa phases, and missing the transition between them can force you to leave the country early. Building your job search from your very first semester is what actually makes the long stay realistic.

Your Two Required Visa Phases

Weighing The Benefits Against The Risks

• Benefit: several years of professional experience in a hub like London, Manchester or Edinburgh makes your CV far more attractive to global employers.
• Benefit: working through these years helps you recoup your tuition and living cost investment far better than leaving after a few months.
• Benefit: 5 continuous years specifically on a Skilled Worker Visa can make you eligible for Indefinite Leave to Remain, though time on the Graduate Route visa does not count toward that clock.
• Risk: the Graduate visa itself costs 822 pounds plus an Immigration Health Surcharge of 1,035 pounds a year, all payable upfront.
• Risk: if you reach the end of your Graduate Route without a sponsor lined up, you will be forced to leave and your 5 year plan ends early.

My Advice

Start your job hunt in year one of your Master's rather than waiting for graduation, since UK graduate schemes typically open a full year ahead in September or October. Target sectors with a strong sponsorship track record, such as technology, healthcare, finance and engineering, and check the official Register of Licensed Sponsors on GOV.UK before you invest time interviewing with any company.