MSI RTX 2080ti Gaming X Trio -> RGB Lights Problems

I don’t know if I’m in the right sub-forum here, but I’ll just give it a try.
For a while now I had an MSI RTX 2080ti GAMING X TRIO and a new case with RGB fans etc.
Since I don’t like excessive RGB, I set all the LEDs to white, which is mMn. They look much better.
However, the LEDs cannot be changed by the GPU using any software. First, of course, I used the software provided by MSI: MSI Center with Mystic Light => The card is recognized, the effects can be applied and saved in the program, but the actual graphics card does not change anything and keeps annoying me with all the colors of the rainbow.
In between, I’ve tried all kinds of other software, SignalRGB, OpenRGB, etc. Same game there. In all these programs the card is recognized without any problems and effects can be applied and also saved when you open the program again at some point, record the RGB card. It also can’t turn off the LEDs or something like that.
On the MSI side, I found an older version of Mystic Light (v.3) under this graphics card’s utilities. With this other people with a similar problem have had success, but with me everything is still the same as before.
I also don’t think other software I use for the fan/keyboard etc, for example, interferes. In the meantime, I have deactivated all of them to test and restart.
The motherboard is relatively old, it’s MSI X99A GAMING 7. (As far as I know, it was one of the last motherboards before all the RGB elements were inserted on the motherboards, it doesn’t have its own RGB header or LEDs, etc..).) As a last try I updated the BIOS there, but it didn’t work. Then it occurred to me that I could easily set the LEDs on my previous card (PALIT GTX 1070), so they shouldn’t be on the motherboard either.
I really can’t get any further and have spent hours on it, but a big RGB block in the middle of the off-white LED’s is driving me crazy
Meanwhile, I’ve been through almost all stages of grief and slowly come to acceptance, but I wanted to start this one last try. Maybe someone had a similar problem or had an idea.
Thank you for every contribution!

LG