I think this dark-to-light delay is normal if you are using the built-in mini-LED display. I've noticed it myself. The backlight LEDs actually dim for dark scenes and light up for bright ones, but they do not respond instantly; they lag some milliseconds (a frame or two) behind the video.
It's most obvious if you just watch the end credits for a TV show — white text on a completely black background, where it immediately "pops" from one set of credits to the next (not scrolling) — you can see the mini-LED backlight take a moment to adjust to the new position of the text and light up zones accordingly.
I see this as a trade off that is "worth it" given the other benefits of the mini-LED display. However, this problem should go away once Apple puts OLED displays in the MacBook Pro (2025-2026-2027 timeframe?).
For the "traces when switching windows or tabs", I have never observed that myself (16" M2 MacBook Pro). I do wonder though if it would behave better in this manner if you set the display to 60 Hz, instead of ProMotion, in the macOS display settings.
You can have your MacBook serviced by shipping it off; you don't have to visit an Apple store. However, if this is just "how it is" with regards to these displays, that won't do you any good.