The retro handheld scene hasn't stopped growing ever since we started making video reviews on them back in 2019, we're forced to update our best list every month because of it!
This year especially has seen some aggressive competition in the budget and premium space, such as the recently released RG34XXSP, the GKD Pixel 2, and the larger devices such as the Retroid Pocket Flip 2, AYANEO Pocket Ace and more.
There's no stopping these companies, and they're all racing for our attention, but none of them have yet to pull the trigger on a affordable dual screen device (AYANEO release the Flip DS, but that's overkill).

There's no wonder no affordable ones exist yet, as its more expensive to produce, theres very little demand for it seeing as it would become a dedicated Nintendo DS emulator and again, lots of competition to fight with. Most retro gamers already have emulation devices.
If any company is going to do it, my bet is on ANBERNIC doing it first, but not necessarily the best. ANBERNIC have a history of going for quantity over quality, but sometimes it pays off.
Recently MaxZhou, one of the owners of ANBERNIC has been showing interest in dual screen devices across Chinese social media, asking his community what they think, alongside leaked files of a gaming device that features a slide up portion to reveal a second, much smaller screen.

Max shared images and concepts of what a ANBERNIC gaming device with two displays could look like, showing interest in a mobile phone and gaming device hybrid while commenting to replies on Baidu with "the future is coming soon".
I must say Max has shared a n array of concepts in the past that has never come to fruition, so take this with a big pinch of salt. ANBERNIC has never made something like this, it's unlike them to invest in a mobile phone/handheld hybrid.
But I do believe affordable retro handhelds will need to adapt an innovate, forcing ANBERNIC to at least test this market, because although there is "little demand" for it as i mentioned above, there is still thousands of gamers wanting a dual screen retro handheld emulator. Being first could mean selling to an untouched market, that will then become hard to sell too once they already have a dedicated DS handheld emulator.

Max even showed off a AI produced concept of a mobile phone pairing with what looks like a retro handheld "base", allowing you to attach them together to create a dual screen device, like an add-on accessory rather than a dedicated device.
This concept follows their design principals of the older metal series of handhelds they released back in 2022 such as the RG353M, one of my personal favourite retro handhelds of all time.
All of this attention, and market research on dual screen devices makes me believe that ANBERNIC are cooking up something, likely to reveal later this year as they tend to work fast.
I think it would be a good move for ANBERNIC to pursue this earlier rather than later, before the market floods. However, I believe if ANBERNIC did release it, it would be $200+ device with similar specs to the RG557.
I'd love to know your thoughts about this rumour in the comments below!