I honestly don’t know what would be the limitations of this (or if it’s even possible).
As you know, nvidia has officially killed off SLI support at the driver level for the only SLI capable card in the line up, the 3090. Currently the only way to actually use SLI in many games for the 3090 is to setup SLI with “surround view” in nvidia control panel which essentially allows us to connect 2 or more outputs from the SLI cards (can be 3090s, 2080s, 2080ti, any SLI card really) and essentially make each GPU render a different screen. In essence if you have 2 QHD monitors and you hook up 1 cable from each one to each GPU in SLI, that GPU will render half of whatever is being rendered for that game.
Currently I am aware certain gaming monitors support the Picture By Picture mode (locked to a specific refresh, usually 60 hz) where it can take 2 inputs and essentially compose two screens with each taking up half. The Samsung G7 32" and 27" have this feature for example and have allowed people with SLI configurations to actually render at higher frame rates simply because each GPU is rendering half the screen. On a QHD screen that would mean each GPU in SLI would have to render a resolution of 1280x720 each or 1920x1080 for the 4k eve model. Currently this is the only way to get anything close to SLI 3090 (unless the game explicitly supports explicit SLI) on a bigger library of games and get a decent performance uplift in older games that either don’t support DLSS or just flat out requires more power to run at high frame rates (I’m looking at you Ark: Survival evolved…old game that maxes my 3090 at QHD with all details maxed out!).
I hope this isn’t against the forum rules (I didn’t see anything saying contrary that I could post this link) but here’s a link on EVGA forums where someone showed they got SLI working for 3090s.
I agree this isn’t a required feature, let alone a feature that should have high priority but if it’s possible to implement this feature, that would be another extra utility that eve spectrum would have over everyone else.
Now for the bad news
There are some caveats to the above idea that I would like to mention, they mention there’s issues where the middle of the monitor there is sometimes a vertical tear line because the two GPUs might not be matching up. I know SLI works with Gsync enabled but I don’t know if it can be enabled for this configuration to allow for variable refreshes with no tearing and smooth motion. If gsync/freesync is not possible, it’s not a complete loss because you can essentially try to compensate by having overkill FPS to minimize the tearing while having the lowest input lag possible for backlight strobing (and hopefully no studdering since vsync will be off).
As denoted by blur buster’s page here: Motion Blur Reduction (ULMB, LightBoost, etc) | Blur Busters
Exact quote from the page above
" Optimizing For Reduced Input Lag
Blur Reduction modes by several vendors, may add input lag. There are many tips & tricks by users in Blur Busters Forums to reduce or eliminate “strobe lag” for Blur-Reduction-optimized computer configurations.
Instead of using VSYNC ON which adds input lag, one common alternative is the use of an in-game frame rate cap (such as a Source Engine fps_max setting within CS:GO, Team Fortress, etc). This can allow playing with good motion clarity during VSYNC OFF instead of VSYNC ON, while also eliminating most “Blur Reduction microstutters” issues. And also avoids the input lag of VSYNC ON that can interfere with competitive first-person shooters (FPS games). See HOWTO: Low-Lag VSYNC ON.
An alternative method to reduce microstutters during VSYNC OFF with scrobing, is to use framerates far in excess of refresh rate (such as 300 frames per second or more).
As mentioned in bold there, overkill FPS can be used to make backlight strobing even better by reducing input lag and microstudders! (microstudders are the devil and can ruin a good backlight strobing experience). Needless to say, this feature would be amazing if it can be enabled with backlight strobing at the same time 
I understand that if the above is not possible it’s fine, I don’t expect this would be possible on the eve spectrum but I at least would like to be the first on this forum to at least mention the idea if it can exist
Needless to say there’s probably less than 0.5% of people left who probably still use SLI for gaming so I don’t expect this feature to get any traction but I do want to bring it up in case eve spectrum does indeed support Picture by Picture (with or without Gsync).
but say you get a fixed refresh in PBP at say 100 hz, you can in theory still play at 200 fps with no vsync (with RTSS fps cap for frame pacing OR scanline sync) and get less input lag with smooth motion with less studder for backlight strobing. At least in theory, again I can’t test this because I don’t have such a monitor.
. Thank you very much in advance ^^