Buy your graphics card NOW
I'd be waiting until 2028 and substantial additional memory supply hitting the market myself if you can wait.
If you're trying to decide between buying a video card in, say, mid-2027 or now, okay, yeah, maybe then it'd be better to buy it now. But if you don't have a really strong need to upgrade in late 2026 or in 2027, you're probably going to get more bang for your buck by waiting.