But I am switching around my system and need subwoofer advice.

Currently my living room TV (large open room with kitchen) has been working off a vizio combo sound bar/wireless sub for like 7 years via optical. No complaints.

Living room and kitchen each has 2 ceiling mounted speakers that came with the house but not set up as a theater. I'd say the two living room speakers are middle of the room, left/right. The two kitchen speakers run perpendicular.

The older Sonos amp that came with the house just died so I'm replacing it with WiiM that has hdmi and subwoofer Jack's that the Sonos lacked. We used the Sonos for playing music, it wasn't connected to the TV.

With the new WiiM I'd be able to run the TV through the ceiling speakers and add a subwoofer to the front of the room (and add a 2nd sub to the back), but then I'd lose the soundbar.

Question is... What's a medium range subwoofer that sounds decent under $500 or so that can run in series with a 2nd subwoofer?

And.... Is this even advisable given my current setup?