I would call Yamaha and try to find out the frequency range sent when using the extra bass feature. Back in the day the Yamahas just passed 90hz low pass but it was called bass both instead of extra bass. The review here on Bass Mgmt pictures a A3030 and says 50hz to 80hz is boosted so you may need to verify it with Yamaha or trust it.
If Yamaha support doesn’t know you could search thru tons of owners threads on AVS forum or post there.
If you want a pure solution you could imagine this is a 2ch setup with no bass management and use the sub to set the crossover but you are using LFE... Others would know more than me about this old school approach...
Practical solution is use the extra bass and tune the sub to your liking or on the fly. Or like I mentioned use 11 ch stereo dsp and make sure side speakers are set small and use that for LFE to forward to your mains via the LFE in on your BP2000 towers.
Creative outside the box idea would be to use either the scene or global settings to store a setup that tricks the 11 ch stereo dsp setting by using sides as small like above however not actually using the sides physically. Ya I’m reaching a bit here.
Honest assessment is the built in sub approach at Def Tech was the most successful in their center channels where you are putting the sub inside the center at mid wall. You are compromising to put subs in the left right instead of mid wall or in a corner of a room...
Curious the history of how you assembled the system and if only the 3070 is new? Good luck!
https://www.audioholics.com/home-theater-connection/utilizing-extra-bass