The MSI X470 Gaming Plus motherboard supports up to three GPUs.
The MSI X470 Gaming Plus motherboard supports up to three GPUs.
Check the product details—it mentions 3-way crossfire. https://www.msi.com/Motherboard/X470-GAMING-PLUS However, you have three NVIDIA cards (one different model), so you can still connect them and use them for rendering in applications like Blender. SLI won't work for gaming. The motherboard doesn't support SLI.
Observe that every card Steve employed features additional power connectors, reducing the current drawn via the PCIe port. Some models, like Quadros, consume less energy. The OP is running a 1050ti, which routes all power through the PCIe slot.