Accurate and revealing subwoofer

It has to be less powerfull because the room side to fill with is quite difficult with some bass frequency accumulation at the ceiling level. I am applying some room correction though with Roon’s DSP engine

I think it’s really important to get your fist sub dialed in before deciding to go with a second. Minimize the bass peaks because those will force you to set your overall sub volume too low.

Consider bass traps like Gik’s corner or soffit traps.

Roon is great but it won't work when you have 2 subs.  You'll need a miniDSP like device to give you separate control over each sub.

Look at the AM Acoustics room mode simulator and try to place your sub, speakers and listening location out of the lowest bands.

PS - You don’t need a sub to be less powerful, but one important component in adding a subwoofer is matching the dynamic range. You don’t want one sub that starts to compress when another still has plenty to give, so I personally stick with the same, or get a larger sub. If you are going to use DSP anyway a larger sub won’t overpower your room if EQ’d well.

It will however give you much better dynamic range.

The JL Audio subs with built  in room correction are amazing, but also super $$$$.  I can't spend that kind of cash, so I do with Hsu and MiniDSP and am very happy.

my favorite (dream) subs are Monitor Audio and KEF.

I would find it really challenging to add subs to floorstanders (mostly because I am ignorant but curious)

Stick with the D110. I’ve owned one and I thought it was outstanding!