Unless you’re going 8+ channels, DDR5 is not going to be able to compete with VRAM. (and even 8 channels is on the slower side in terms of usability)
From what I’ve read, support is the defining characteristic for 32GB cards. nVidia is king, requiring almost no fiddling to get things working, the software on AMD is good enough that you can run almost anything with some problem solving, but the intel is a headache because the software only runs with specific versions of model runners, if at all. If you go multi-card the problems increase to the n-th degree. (look up the RCCL and BattleMatrix problems on this forum) 24GB works, but with limited context size. For me this means limited usefulness. So I’d say that 32GB is realistically the theshold for any useful LLM use, but that might a kind of snobism that I have in me.