Sorry, this is asking a lot.
The job offer in Dubai in the DIFC is AED 420,000 per year (about £85,000), the current job in the UK is £90,000, which is £60,000 after tax.
The Dubai offer bonus is AED 70,000 but although the goals are easy they are discretionary, probably won’t be fully paid out and only after review, 1.5 years once paid. London is the same – discretionary and around £10,000 GBP

(1) Cost of living seems higher in Dubai – food, taxis which are relatively cheap but add up and I can’t drive, entertainment.
(2) Plus return flights to UK 4-5 times per year as my holiday costs £2-2.5000 per year and hotel accommodation in London is expensive
I think (1)-(2) will cost around £5-10k.

(3) If I rent a 1 bed in DIFC (so no commuting) for around AED 80,000 plus all bills, agent commission, 5% tax etc. I think it will cost around £20,000 a year.
However, I have saved enough for a deposit on a house in London, and am currently in the market. I won’t be able to buy until I have to go out if I accept. If I refuse Dubai, I buy a house, then obviously there is stamp duty etc. about 10,000 cheaper than spending 20,000 in Dubai. And I’ll get some house price appreciation, which means it’s probably closer to a 20,000 saving.
I can buy in Dubai, but it would have to be a buy to let, and I don’t have enough for a 25% deposit (on something reasonable with a decent return) until the end of the year next.
And when I get a buy-to-let, the interest is much higher, even on an interest-only mortgage.

So from where I stand, I would break even or maybe go home another 5-10,000 to Dubai if I was very lucky, but that seems negligible financially.

In terms of lifestyle, it may be another story. I don’t think London has recovered properly from Covid. I have worked here for 10 years and lived here for 30 years and fancy a long term move. The dating scene is a little dark, but I’m afraid the Dubai scene is even darker. I’m a tall, white, attractive (within reason) guy. My fear is moving from fridge to fridge (from home to office), venturing to the beach on weekends, having the occasional brunch, but otherwise spending most of my free time at the sports Hall.

If I stay in London, I’ll probably have a much higher paying role in a role. Almost twice the current base. In Dubai the market is smaller and I think I’m stuck in this business for a while.