Please do not flame me about it. But I bought a used (Dell) AMD Radeon RX 6300. US vendors start these cards for about 40 bucks plus shipping at the moment.
All tests were done with an AMD 5600G, not on the Orion O6 itself. My order shipping is delayed.
Yes, you absolutely could grab any older Radeon series or, if you have a bigger case in mind, use an Intel ARC. Or, if you have no ears and want a single-slot, low-profile card, use the Sparkle A310 ECO. But for a steeper price tag (EU 110+€). But with transcoding plus AV1.
Older Radeons are maybe a small fraction cheaper, but I tested some of them and they all use more power, even under idle, just linux desktop, situations. The (RDNA2, TSMC N6, TDP 25W, TGP 32W) Radeon RX 6300 uses 2W for that. Goes up to 5W for browsing (just moments of loading, most times under 1s, then back to 2W), office stuff, and up to 8W for 1080p video decoding (different codecs, browser and players that use HW accel). Fan stands still all the time and the card stays cool. And those values are a good portion lower than 400/500/600 cards I could test or read about in tests. And if you want at least some video decoding, you probably do not want to go below the GCN4 / UVD6.3 series from AMD (RX 400/500/600 series).
I tried a (18W passive, but very loud spool beeping) R5 220 (which is a 40nm rebrand of a rebrand) and it was laughably bad - returned the card.
So, just my two cents for a viable option, silent, low-power, as a drop-in solution with working mesa driver support, low-profile, single-slot (working with my passive-cooling ITX case with 1 low-profile PCIe slot) with at least vpu decoding capabilities.
Found mine on ebay, just search for “Radeon RX 6300”, sometimes writing is “RX6300”. Vendor just raised the price from 40 to 46 $ plus shipping.
Ah yeah, it sucks at 3D, as you probably could have guessed with 2GB VRAM connected at a 32-bit bus. But strangely not as hard as you would expect.
These cards are a rare find, by the way. So you have to get lucky to get one. Please do not scalp them (seen variants with prices over 200 bucks - yeah, right?!).