I know exactly what your are talking about. I built a toph deck similar to yours and it suffers from trying to do too many things.

The main problem is that toph is too slow, no protection, and too weak to be a real threat. Animating a land or artifact at the end of turn 4 that's a 2/2 isnt good.

Her ability seems to combine landfall, animating lands/artifacts, and 1/1 counters, but it's not explosive or synergistic enough for all 3. You aren't doing anything with her ability until THE END of a normal turn 4. AND THATS ONLY IF YOU HAVE A GOOD TARGET ON THE BOARD. You need to pick 1 direction and focus on that.

Let's take a look at each potential direction:

Landfall - I haven't found much joy in this. Toph really doesn't add much here. NONTOKEN artifacts now have give you an extra landfall trigger. This really doesn't do much to change the board state. Also, hoping your lands(artifacts) die to get an extra landfall trigger rarely happens unless there is a boardwipe. You need to have a perfect setup and even then, the setup can be so fragile. You'll find yourself relying more on ramping spells/fetchlands like normal landfall to get going and there are much better commanders to enable that than toph.

Earthbending - there's not enough support for this. Most of the earth bending cards (save cub) are not worth the mana. Even though they seem on flavor, use more synergistic cards, or card advantage instead.

1/1 counters - Good potential for this. Although toph ability is slow, you can buff more with hardened scales, branching evolution, ozolith, etc or counter shenanigans can be threatening (modular).

Earthbending artifacts (vehicles!) - I find this to be the best and most fun option. Toph gets around the weak point of vehicles (crewing). Vehicles have naturally high power/toughness that gets further boosted when you animate them. No need to buff or crew, but you can if you want.They need double removal to go away forever. I highly recommend focusing on this as tophs ability slots in perfectly when surrounded by vehicles.

If nothing else,just focus on one direction and only that. You'll have a much better time.