After a week I got so frustrated I just bought an EdgeRouter ER-4. Everyone and their dog saying they are the best bang for buck. I have a Gig fibre and apparently this thing just works.
Well... While it is a pretty sexy box and the UI is marvelously slick and it is impressive. Two things are killer features.
A)My OpnSense box (admittedly easily outpowering the ER-4) gets about 100mbit more downstream and 200mbit more up (ER-4 maxxed out at about 720/280, where the OS box did 870/510)!! That's nothing to sneeze at. Especially the up, which is why I have that link in the 1st place. And then, killer #2 (which I missed before buying), the LAGG support is well...only really theoretical.
I did try a lot of settings and googling but no avail. Also the same issues as with OpnSense appeared so it wasn't that. I hope I can return the ER-4 on Monday otherwise there will be one going here. Still a good box but you can have more for less I guess. Just thought I'd share. I'd definitely go for it for lower rates but then probably a smaller ER would do the job too.