Hi Austminer, I'm sorry for rejecting the run, it is back in the queue. There are some discrepancies with how the game looks between 1.15.1 and 1.15.2 that I wasn't aware of, that made me think it was ran on a non-approved launcher. Thank you for creating this thread to rectify the mistake.
For your second question, check if you followed the steps as shown in this video at this timestamp
Gamma cannot be modified above 1.0 for version 1.19 to maintain vanilla parity, sorry.
Yes. You can also check via going to https://redlime.github.io/MCSRMods/.
You can read detailed rules on texture packs at http://bombch.us/DOOK. If you're not sure, err on the side of caution and open a thread in the java speedrunning discord. xqcL
If you have a discord account, we can continue this conversation in a #help thread in the MC java speedrunning discord. Here is the invite link if you are not yet in the server: https://discord.com/invite/jmdFn3C