Using upstart- too good to be true?

Hi,

Recently I got a loan to pay off some credit card debt.

It was 18k, upstart gave me a rate of 7.5% 60 payments.

I paid off the credit cards and my credit score went from 730 to a 755 in one day even with the hard credit check.

My utilization was under 20% which is maybe why I got a good rate? But it feels too good to be true- is there anything hidden and what was everyone’s experience? I looked at the agreement and it doesn’t say variable rate.