It's weird, if the card is hashing normally now you can conclude that is a temperature problem
If you already tested with fans at 100%, another thing that could be are the thermal pads, can you check if thermals are in touch with heat pipe?
Or maybe the position of the card in your rig, is there hot air blowing direct to this card?
I have never disassembled a GPU, lil afraid to do so. I have been seeing some videos on youtube.
Does GPU also have a thermal paste similar to CPU, If I decide to; can I change the paste and see if it helps?
I had this card in an 8 GPU set up the usual way we set up rigs on a mining frame, spacing between cards is enough though to avoid hot air from the adjacent GPUs to directly blow on this.
Shall I get a GPU cooler fan something like this might help
https://www.amazon.com/gp/product/B07XCFB5WP/Weather wise it is getting cold here in Arabia so I will not run into heating issues until March with this type of table fan set up, but after that.....