So assuming Gen12/Xe is the same which isn't a safe assumption, it would be:
96EUs*2 = 192 ALUs * 4 32bit ops/clk (768)
192 EUs*2 = 384 ALUs * 4 32bit ops/clk (1536)
No, you got it right.
An easier way to remember it for those that were in since the early days is think of it like the original Pentium.
The Pentium was the first superscalar processor featuring 2 decoders, but they were not identical. They were called "U" and "V" pipes. In a way the Intel Gen graphics are similar.
Think of each EU as being a core with 2 way issue. Each issue pipes allowed for 4-way FP32 SIMD execution. Realworldtech has a great article that explains this. The functionality between each ways are not identical, although for 3D gaming it is.
So it means that TGL_LP has 768 ALUs, and Gen12HP has 1536 ALUs?
I think the Gen12HP config shown in that tweet is only a possible configuration and not the base. If you looked at earlier driver leaks they have different configurations.