TheScythe - do you have a specific model number to identify the variant of the K10? I looked up the stats and the GPU it uses depends on the variant (which presumably depends on the market region).
So judging by the information in this thread and looking up device GPUs on gsmarena, we have results something like this:
Honor 9 Lite: Mali-T830 MP2 - broken
Alcatel A5 LED: Mali-T720MP3 - broken
OnePlus 5T: Adreno 540 - working
LG K10 (2016): Adreno 306 - K420N; Mali-T720MP3 - K430DS, K430DSF, K430DSY
LG K10 (2017): Mali-T860MP2
At least one of the K10 variants above broken
It's not a lot of data to go on, but it would make sense if this is a GPU driver bug in Mali GPUs affecting OpenGL ES 3 (WebGL 2). The more devices we can test and get results on, the better. So if anyone else can test on additional devices and let us know if it works or not, that would be helpful. Then we can look up the specs and see if there's a correlation with the GPU.
We have data indicating ~50% of Android devices use Mali GPUs, so blacklisting anything with "Mali" in the GPU name from using WebGL 2 would have a high impact. I think the best approach would be if someone can produce the most minimal project possible that demonstrates the issue and then file a bug with Google with our device testing results and see if they can get to the bottom of it.
For the record I edited the thread title to better reflect what we're trying to do here.