I was configuring my M5 MBP preorder and 48=>64 was 250 EUR so not sure if they cut prices or your numbers are outdated ?
Prices in the US are usually much lower than in Europe. I just checked and 48->64 ram bump is still $200
I just did a 14" MBP with M5 Max, 128GB RAM, 4TB SSD, nano-texture display. Price difference is $5849 vs 7004 EUR ($8136).
US prices are often low enough that it's almost worth the flight just to grab one.
14' MBP M5 Pro 64GB - $2999 or 3449 €