I have several sets of Kasa HS210 (3-way) installed in my house, one of which has a 4-way switch on the circuit. This works without any issue; in fact, you can install the HS210 without touching the 4-way switch and it will function correctly.
Let me know if you have more questions in terms of wiring. I only have one HS210 on each circuit (instead of replacing both 3-way switches) to save money, which also works, but you have to replace the 3-way on the live side, not the load side.
I replaced my 4-way switch with this to more closely match the aesthetic.