How to Paint Non-Repetitive Textures on Terrain with Adjustable Brush Size (and No Blending)?

Hi everyone!
I’m relatively new to Unity and currently working on my own small project involving a custom Terrain. I’ve spent a lot of time with the built-in Paint Texture tool, but I’m running into a few big limitations:

No way to set different brush widths and heights (independently) when painting. The tool only gives me a single “brush size” slider.
Textures blend and tile by default, which is great for grass or rock, but not for detailed patterns (like floor tiles or specific decals) that I want to place without any repetition or blending.
I want to paint certain detailed textures (e.g., a unique floor design or a specific pattern) onto my Terrain in specific areas. However, these textures:

Shouldn’t tile (no repeating edges).
Shouldn’t blend with the underlying Terrain textures (I want a clean, sharp boundary).
Need to be resized in a custom way, such as adjusting width and height independently (e.g., a rectangular shape instead of a perfect square brush).
I’ve tried the default Terrain Paint system, but it always tiles the texture and blends it with other layers. This makes sense for most natural terrains, but not for my case. I’ve also looked into placing normal GameObjects (like a plane or quad) with the pattern texture, but that can be complicated when the Terrain is uneven. Decals come close, but I’m still not sure if they handle large, irregular shapes well, or how to keep performance in check if I have many of them.

My question is:

Is there a straightforward way or existing tool/asset that lets me paint a non-repetitive, non-blended texture onto Terrain while customizing the brush width and height separately?
Should I be looking at something like a custom shader for the Terrain, or a special plugin like MicroSplat or MegaSplat that can stamp textures without tiling?
How do I keep this efficient for a decent-sized map, and how do others manage unique patterns without resorting to tiling?
I’d really appreciate any guidance, best practices, or asset recommendations. As a newcomer, I’m open to suggestions on whether I should skip the default Paint Texture tool and use alternative methods (like Decal Projectors, custom mesh overlays, or third-party Terrain tools).

Thank you in advance for any help! Any step-by-step instructions, personal experiences, or references to tutorials would be fantastic.

Cheers,