Those old MacBooks can't reliably play 4k and will struggle with 1080p YouTube without running the fan due to software decoding. I think the newer ARM-based Apple products will have much better resale value than the Intel ones. I wouldn't buy an Intel MacBook ever again after having used M1, the difference is night and day. The cheapest M1 MacBook Air with 8GB RAM will do literal laps around any equivalent Intel machine.