First, the fact that you had a separate booking OTP-SLC is not relevant here.

What you really need to figure out is the actual reason for the delay, it could very well be that there were several reasons, first the airplane couldn't fly due to weather, then once weather got better their staff were out of hours for example, then you can possibly claim EC261 compensation for your delay BUD-OTP, I'm not sure what "fuel issues" might be and whether that will somehow be considered as extraordinary circumstances.

In addition to the potential compensation they should refund you the hotel and any reasonable meals (e.g. dinner + breakfast).