While I agree with the general statement that tensor core are better to have, memory on device is a bigger limiting factor in the long run.

Depending on the model, deep learning can require a significant amount of memory for training. I would suggest you save a little more and go for a 2070 (8GB) or if you can swing it the 3070 with 8GB.

(Edited with correction on the amount of memory available for the 3070)