I have mac pro 2017 which is probably of the same age, if not older, and the battery life is just so much better.

Jumping to the M-series would blow your mind, at least it did for me. After 8h of heavy usage my MBP still has enough left to just browse or watch something for at least another 1-2h, traveling by train and using it for lighter tasks had the battery last 14+h.