Thank you so much for sharing this. It's gotta be tough for you. But it's a great learning experience and others can hopefully learn from your mistake.
This is why it's so important to regulate ALL heat sources.
I would definitely look into a RHP. I have them in my PVC enclosures and now that I have them I'll never buy another heat lamp. But, obviously it'll have to be regulated. You could actually do away with the belly heat if you go with an RHP too. RHPs make it very easy to set up a proper temp gradient. You could even use the thermostat that's currently attached to your UTH so one less thing to buy.
And I do have to agree with Bogertophis, those half log hides are unfortunately not a great choice. BPs crave security and those hides offer next to none.
Again, thank you for sharing this unfortunate situation so others can learn the importance of regulating ALL heat sources. I wish you and your snake all the best.