Please do not confuse the IDE (the scene editor) with the limitations of the renderer (PixiJS and Chromium).
Keep in mind that some form of texture resolutions limits do exist on all platforms and engines, and older hardware will have smaller limits.
However, since these limitations have now been made clear to you, and you are proceeding anyway, I wish you the best of luck and that you find some way to do what your goal is. This thread will now be closed.
Edit with more details:
For the OP, or anyone who may have interest in the technical details-, here’s a more thorough explanation from some quick research:
Max Texture resolution is going to commonly be a combination of 3 things, the maximum VRAM available on the device’s GPU, the maximum texture limit on the renderer, and any memory limit of the operating system.
As an example, for someone with a 3080 GTX with 12GB of ram: The maximum texture it can render in WebGL is 16384x16384 at 32 bits. A single texture after it is decompressed to run in memory at this resolution would take 16384x16384x32 bytes, or 8589934592 bytes, or 8.59 gigabytes of VRAM. Meaning this GPU, if unrestricted could only show 1 texture at this size.
Alternatively, most browsers and web renderers also have a maximum texture/image size limit. Last reported maximum for Chromium is 4096x4096x32 on desktop. (Firefox only allowed 2048x2048 until a year or two ago)
Then there are OS limits, although these are usually restricted to mobile. These vary by OS version so going into specifics, but iOS, for example, has a GPU capable of slightly larger than 5000x5000, but hard limits it to 4096x4096 as recently as data from last year.
No matter what the largest supported texture for any combination of these are (GPU, Renderer, or OS), you will always be limited by the smallest maximum supported of the three.
Even multimillion dollar engines like Unreal are restricted by this, which is why they have had to develop and implement technologies like texture streaming to allow for faster swapping of textures. Keep in mind the above scenario is for the GTX 3080, one of the top of the line GPUs on the market. GPUs with less VRAM or slower VRAM will run into even lower maximums. This is also why when you search around the internet it is generally recommended to never go above 4096x4096x32 even for desktop 3D game development (or 2048x2048 for mobile), to ensure you support the largest market possible.
Hopefully the above details helps other people interested in understanding why games even amazing looking 2D like Hollow Knight and Spiritfarer do not go past these limits.