Small frame subwoofer

I am somewhat space limited and "optically" constrained by the Queen in adding a sub to my Manley Stingray/Tannoy Autographed Mini’s system...

the large REL frames will interfere with a door to the deck... a stacked system seems better suited...

I want a sub to complement and obviously improve the bass, with an app or a remote function to dial it in.... my budget is under $5k... well loved used is fine as well... thanks in advance for the council

and further to the above... anyone have expertise with  Canton Vento 12 sub?