I essentially just did this as a total beginner and it worked. (I have built my own gaming PCs and took basic/Pascal programming in HS, but have no real network experience)

I had some old enterprise mini PCs, added a second NIC to one and put Opnscence and pihole VMs on it. I ended up doing PCI Passthrough for the new NIC for the Opnscence VM so the WAN/modem is isolated from the host. Bit a simple bridge works. The management LAN NIC is just in bridge mode.

I’m probably too new to be offering advice, so I’ll just pile on the encouragement. You can do it!