Having trouble using atlas on an avatarto combine all textures

1st image is before atlasing, 2nd is after, and 3rd is what the atlased avatar looks like in unity with the original one. whenever I atlas the avatar, the shaders break, the textures get blurry, and the textures repeat/wrap around and idk how to fix this

When you say that you used the atlas feature, do you mean that you used the CATS plugin for that ? If so what version and on what belnder variant ?
Usually those kind of issues can be because when doing an atlas the resolution of the merged texture is lower than the individual textures you had before, you may have to tweak the settings to either increase that value or work the uv to avoid stretching the texture too much making it blurry. That’s what i would look for personally