Good news! I managed to pull together a 128x version of the Vanillaccurate pack for OSBES v1.9.2.
Here are some yummy screenshots with this pack, you can see the increased resolution makes for a lot crispier details. Performance-wise it didn’t hurt my FPS much so if you have a good GPU and at least 3-4GB RAM on your phone you should have very decent results! If you already have high FPS at 64x you’ll definitely be able to run 128x at fast framerates provided you have enough memory available.
Make sure to clean up your RAM a bit by closing unnecessary apps/services before launching Minecraft if you have trouble loading the 128x pack.
Download can be found on the original v1.9.2 release page. Click on the link below: