Our official runtimes are compatible with pixijs v7 and v8.
I guess that if you are using pixijs v4, you are using the unofficial pixi-spine runtime. We don't know the pixi-spine, so we can give only general advice.

Spine textures are always loaded as pixi textures in pixijs runtimes. This means that if you access the pixi texture from the spine model, you should be able to control min/mag filters, and mipmaps.
If you have a bigger texture that the target resolution, you probably want to enable mipmaps.