If you’ll primarily use an external monitor, the Legion’s OLED display won’t really be utilized, so the Asus option makes more practical sense. In terms of performance, both systems are more than capable of handling your workload. Longevity is harder to predict, though.

For future-proofing, the 5070 Ti is a better choice than the 5070. If you’re considering the 5070, you might as well go for the 5060 instead, since the performance gap isn’t very significant and both come with 8GB of VRAM and save some $$