I had a few three switch circuits, so like your 4 switch, but I only had one 4-way in the middle of the three ways.
In a four switch circuit, three of the switches can just become their own 3 switch circuit, by removing one of the four ways in the middle.
How you do things all depends on what box the line comes into and what box the wiring to the lights come into. In mine, the same box has line and the light coming in, so a smart switch by itself there would control the lights, with the other switches in the four way circuit disconnected.
This is what I have:
I bought the Zwave dimmer switches that have the "traveler" terminal. What that terminal does is detect if a circuit is opened or closed, and flip the switch when it detects a flip of the circuit, much like a Shelly or other relay switch does, when the switch wired to it is flipped.
So, I used the traveler terminal on the main Zwave switch, with the remaining two switches in the circuit wired to be a three way circuit instead, just to flip the traveler terminal. I had to remove my four-way in the middle, replace it with a three-way, and then put a standard 2 way switch on the end of the circuit.
You may have something like this:
Or, you could have the line coming in at the ceiling light fixture, even. (older builds)
The main thing is, you have options, but with each you need to understand your wiring first. The switches I used with travelers have been Ministon, but they don't seem to make the in-wall Zwave Decora switches/dimmers anymore. Eva Logix worked this way, but those also crashed my network so I had to replace them.
GE/Jasco use companion switches, so that is a whole other option, where there is wireless signals between the switches. Their traveler is not a dry contact traveler like I'm talking about.
Then there are the true 3-way smart switches, that can be drop-in to act like a standard 3-way, depending on how your circuit is wired.
