Is this what I’m looking for?

Hi,
First Time doing beef ribs.

I tried to low and slow it. Went for 120 Celsius for about 3/4h. Then temp started to climb to 150 and when I noticed internal was already 80 something so I covered the piece with baking paper (didn’t have any butcher one around).

After that point I had some difficulty decreasing back to 120, even with mostly closed vents. So I think it must have reached 95C internal at about the 5/5.5h mark.

It tasted great, but I wonder if the fat should have rendered a bit more?
Even if the inside melted in my mouth, I found that the outer (skin?) layer was quite rough, did I burn it a bit?

I think I also made another mistake, I used a sugar containing rub. I don’t think it burned, or at least no acidic taste was present, but wonder what other seasonings you recommend!

Thanks!