Unity-Android build size stuck at ~129 MB due to Sprite Atlas (95% textures) – looking for advanced optimization tips [closed]

I’m trying to reduce my Android build size below 100 MB, but I’m currently stuck at ~129 MB, with textures taking ~95% of the build according to the Build Report.

Project Setup

Unity version: 6000.3.5f1

Platform: Android

Build type: Release (Development Build OFF)

Scripting backend: IL2CPP

Target architecture: ARMv7 only

Output: APK

Current Build Size

Total build size: 129.38 MB

Textures: ~95.45% of the build

Assets

~300 sprites (2D mobile game)

Sprite Atlas: Enabled

Largest contributor:

Card Sprite Atlas.spriteatlasv2 → ~105 MB

Audio:

Only 5 audio files, already optimized

Audio is not a significant factor

Texture Import Settings

Override for Android: Enabled

Max Size: 2048

Format: RGB(A) Compressed ASTC 12x12

Resize Algorithm: Mitchell

ETC2 fallback: Use build settings

I cannot lower Max Texture Size further (1024 / 512) without noticeable quality loss, so I’m specifically looking for non-destructive optimizations.

What I’ve already verified

Development Build disabled

Audio is optimized and minimal

No large unused assets

Build Report confirms Sprite Atlas textures as the bottleneck

What I’m looking for

Advanced Sprite Atlas optimization techniques (packing, padding, tight packing, atlas splitting, variants, etc.)

Common mistakes or pitfalls that cause atlases to become unexpectedly large

Any Unity 6–specific texture or build size optimizations that are easy to miss

At this point, I’m confident the issue is not basic import settings, so I’d really appreciate insights from people who’ve dealt with large Sprite Atlases on Android.

Thanks in advance!