Video output in After Effects with nonstandard aspect ratios

I often work in After Effects in compositions with nonstandard dimensions and aspect ratios. I used to have an AJA card for video output that would scale any dimension comp to fit within my 1920x1080 broadcast monitor, letterboxed to maintain the proper aspect ratio. This was very helpful, especially when grading or working with clients. Now I've got a Blackmagic Decklink 4k Extreme 12G card, which, depending on my video output settings and comp size, will either send out a distorted 16:9 image to the monitor, or none at all. Is there any way to get this to work like the AJA card did?

Thanks,
John

Mac Pro (Mid 2012)
2 x 2.66 GHz 6-Core Intel Xeon
64 GB 1333 MHz DDR3
NVIDIA Quadro K5000 3584 MB
DeckLink 4K Extreme 12G

I'm in the exact same situation.
I think that's a major issue, and prevent me to use AE with my Decklink card.
Did you find a solution?

So does Blackmagic want to make it hard for its customers to use Adobe products or is it the other way around.

It would be a logical development for Adobe users to stop getting Blackmagic products.

Any update on this? My DNxIQ with 11.4.1 firmware behaves the same way. 1920x1080 comps in AE work great, but I do a lot of non-standard widescreen work and it just defaults to fill frame/anamorphic which is useless.

Is it that hard to add a dropdown similar to HD->SD with varies options fill, letterbox, crop. Even Media Composer could do this with comps of different sizes.

Is it that hard to add a dropdown similar to HD->SD with varies options fill, letterbox, crop. Even Media Composer could do this with comps of different sizes.

+1
I guess official policy is: use Fusion?

Just checked Premiere and After Effects 2022 and this is still not possible...using Desktop Video 12.3. I can't be the only person who needs this funcationality?