OK, here's some hard data for you:
AMD total share is: 17.51%
(Intel has: 7,78%)
Now we exclude AMD integrated solutions:
AMD Radeon Graphics 2.10%
AMD Radeon(TM) Graphics 2.01%
AMD Radeon Vega 8 Graphics 0.39%
AMD Radeon Vega 3 Graphics 0.25%
AMD Radeon (TM) Graphics 0.29%
AMD Radeon 780M Graphics 0.21%
Integrated total: 5.25%
That leaves AMD Discrete share on Steam survey to be around 12%.
But looking at AMD discrete GPU share based on shipments, that number is waaaay too low:
Here is the NVIDIA vs. AMD discrete market share in percentage from 2010 to 2024. NVIDIA has performed extremely well in the last decade.
pcviewed.com
Also taking into account that Nvidia low end trash cards like GT710 are discrete ones (GT710 does even make it to the list anywhere) whereas AMD low end trash are integrated, we can safely conclude Steam survey does not reflect on real GPU sales.