Is it possible to export sRGB from Premiere or Media Encoder?

Skipping color management is at the top of the CM options, not way down with the sequence. "Preserve RGB" or something like that.

You mention things that could be from several different issues, and that actually illustrates my point perfectly. As ... you simply cannot control all of the variables here. Whatsofreakingever.

First ... are you on a Mac, and more specifically, on a Mac without Reference modes for the monitor?

As if you are, then thanks to Apple, you have a different issue ... an incorrect display transform applied to Rec.709 video displayed images. But only in QuickTime Player, Chrome, and Safari.

For some reason, Macs without Reference modes will apply a display transform for Rec.709 media files essentially equivalent to a gamma of 1.96. The proper standard, as required in the Rec.709 addenda Bt.1886, is essentially gamma 2.4.

On Macs without Reference modes, VLC and Potplayer, and Firefox browser, will more often apply the correct display transform as they tend to disregard Apple's in-OS color management.

So viewing the file in Premiere, well ... what do you have Premiere's viewing gamma set to? If 1.96/Qt, then outside Premiere it should match in Qt player pretty close. Of course, the rest of the world will now see a very dark, overly saturated image. Because the file was prepped for that lighter shadow display setup.

Oh ... and from some rather high-end colorist-level testing I've seen, Apple doesn't stick the best color transform for Rec.709's sRGB primaries, to fit correctly on the monitor's native P3 color space, in their CM either. Which is why Rec.709 video shown in Qt player is not only lighter but "less visually saturated" ... though it isn't just a saturation issue, the hues are actually mapped wrong.

But a Mac with Reference modes set to HDTV will show the correct display transform for Rec.709. And will match other properly calibrated monitors across broadcast and android and PC and TVs.

What about screen brightness?

First, understand what happens with different brightnesses to perceived color. In your work, simply 'lift' the L value and see the visual difference. The hex codes also change, don't they?

Most monitors these days are far, far brighter than the specs for Rec.709. It isn't an issue in general work, but ... I cannot overstate the following:

If you are trying to match specific hue values, you must have the monitors both set as close as possible AND the viewing environment must be identical!!!!!!!!!

There is a reason the viewing environment gets as much attention in the Rec.709 colorist setup specs as the screen. You cannot change the screen brightness, or the room brightness, and get a visually identical image.

As the brightness value of an item changes in RGB triplicate notations, it's relative position inside the chroma volume also shifts a bit. Sometimes, it is visually not that notable. But for brand nutsos with their color chips, it will certainly be notable. The hue cannot remain identical, in physical terms.

This is one of several reasons pro colorists specify both the screen and the viewing situation for all requests for changes to the image.

So it is possible, though a massive pain, to get pretty close to their color chip in a controlled viewing environment on a highly calibrated and profiled monitor.

But that does not mean that you will ever see that same, identical color value, on any other screen anywhere. Period. Because ... you can't.

It isn't physically possible.

Besides, they don't allow for human visual variability. Which is why brand nutsos are simply absurd in reality.

As heavily tested, show people a specific set of hue chips ... then within seconds, ask them to choose what they've seen.

NO ONE ever chooses the chip they saw. People always choose something a bit more saturated, and in hue, slightly to towards the center of the color circle. Note, that as you go toward the center, there are fewer discrete hues! So hue specificity is not something humans are ever good at.

We see color totally as relative to what we think we see, NOT reality. So the brand color chip nutsos are always going for something that is 1) physically impossible with any hardware ever made and 2) not whatever related to actual human vision systems.

Good luck explaining this to them ...