Am I better getting paid alot in one month, 6K

Or 2 smaller amounts over 2 months?

Thanks in advance

PAYE works to mop up anomalies over the course of the year so it’ll make no difference to the amount you pay.

What if I won’t have a job thereafter?

over 2 months will only make a difference if it crosses a tax year boundary (April) as you get a per year tax free allowance, if not as above

tax is generally sorted out after end of tax year – ie all facts known, you may have to pay more or get a refund depending on how accurate your tax code was

If you pay a student loan you’d be better going for the two smaller amounts. No way to claim back overpayment

Depending how much you earn then one lump sum may be preferable from a National Insurance perspective. Tax should iron itself out. The only time it MIGHT be beneficial from a Tax perspective is taking all of it in March or splitting March/April if you cross into new tax thresholds.