Is it true that work visas in the UK are difficult to get and require spending five to six years there?

No, UK work visas like the Skilled Worker visa are not inherently difficult to get if you meet the main requirements: a job offer from a licensed UK employer, the role is on the eligible occupation list, and you meet salary and skill thresholds.

The five-year period refers to the time you must spend on a work visa before you can apply for Indefinite Leave to Remain (permanent settlement). It is not a requirement just to get the work visa itself.