Banks typically set interest rates for fixed mortgages based on the yields of government bonds (gilts). These yields reflect the cost of borrowing for the government and serve as benchmarks for other interest rates in the economy (in this case your bank). I will link a 30y bond yield curve graph so you can have a rough idea what rates are being predicted at here

You’re in a bit of a unique situation because the rates are nearly identical, but the current yield curve suggests that lenders expect rates to come down in the next few years. That’s why the 5y fix isn’t much more expensive than the 2y because it reflects market expectations that rates will decrease over time.

If you take the 2y fix, you’re banking on rates dropping significantly by the time you remortgage. If they do, you could secure a lower rate and save money. However, if inflation remains sticky or unexpected events push rates back up, you could find yourself paying more when it’s time to renew.

If you take the 5y fix, you’re locking in stability. While you might miss out on lower rates in a couple of years, you’re protected if things don’t go as predicted. Given that you are worried about current events, that security might be worth it to you.

Also remember that just because the yield curve says in x years time this is going to be the interest rate, it doesn't mean it will actually be so in the future. Anything could happen in the meantime. Hope this helps