3d models are worth doing well. It's possible to make nice renders but have wildly inefficient meshes and that is not good when it comes to game development, especially for web or mobile where optimization is critical.
Some optimization notes:
1) If a surface is not going to be visible to players, it doesn't need to exist. Delete it.
2) Do whatever you can do with textures, using the textures and not actual geometry. No reason a small detail like a groove in wood, an indentation, crack, nail or screw should be actual geometry, it's best kept as a normal map when your objective is a game engine.
3) Yet, not every PBR texture is always needed for every surface. Some objects really will shine, reflect in spots and need a reflection / specular map, but often there's no logic in doing that, same for any other maps irrelevant to a particular object. Similarly, know that you can use alpha channels to add some small and seemingly complex object detail that is not actually modeled, but it isn't always needed so if it isn't, ditch the alpha channel.
4) Organize UVs in ways that make the most of the UV space and emphasize the surfaces of objects that are most likely to be seen by players. That is, eye level stuff deserves a bit more space. Backs or undersides of things deserve less.
5) Consider size and distance. How much of the screen would the item fill given its size relative to players, and how far away will it be from them? Allocate texture resolution accordingly so things generally look good but don't require vast piles of texture files.
6) Physics meshes are not visual meshes. Make physics colliders simpler than the object's appearance to make processing faster.
7) Detail maps and decals layered here and there can add a percieved detail across massive surfaces like walls - detail maps are a texture layer that faintly tiles, like grainy patterns, and is blended into the rest of the surface and the main image texture. Can provide a vague sense of detail with less texture data. Decals like cracks, stains and so on can be placed here and there to break up any visible tiling.
8) Consider wear, tear, and realist damage. Few things in real life look perfect so the grungy battered and weathered details on a surface add a sense that that surface is real.
The methods described here are typical aspects of my process. I have hundreds of models with many more arriving soon. Thousands of texture maps, well over a hundred decals, overlays and VFX clips. They all go on sale over many holidays. Bundled for under $2 total. They tend to be hyper focused on efficiency over sheer resolution particularly with the models, but that's one of the best strengths of them. They're actually potentially useful for webGL, mobile games!
matthornb.itch.io <--- My itch page.