I may have caught a Transmission fluid brake

I saved a sample of the Tranny fluid at 234k when I bought it last year July 2023 and did a Pan drain & refill with new ATF.
And saved a sample from a couple of weeks ago when I did another Pan drain & refill at 239k the fluid in the bottles were black & blacker.
Then it occured to me what would it look like on a dipstick like a "normal" transmissions ???...if it has one...
So I used the oil dipstick to take a look at as if it came with a dipstick.
And the contrast wasn't as bad as I thought it still shines red.
Not new ATF red but good enough for me. I should have snapped a picture. I may later today.
I contemplated a complete drain and refill at 240k miles or a simple
Pan drain and refill for at least 2 months but all the research on this forum and outside made me take the high road because of possible risks.
In the end I figured the tranny is running like a champ doesn't over heat* (I don't haul or tow anything)
I'd feel like shit if I were to alter or burn it up. Aside from that I don't have 4k for repairs. Even if I did I still would go the pan drain and refill route.
* I've never seen it over 190°F Hou Metro..
Per Scan Gauge 2.