Newish to Macroing

Only recently started playing WoW again after 2 years. Used to use a few macro’s back then but from what I can understand it’s changed? Back then, you could spam 1 button and get insane DPS output. From what I’ve heard, that is no longer a thing?

Don’t get me wrong, I’m interested in learning classes, but macros can be a lifesaver if I’m just trialing new classes and want to do decent DPS, or if I’m just levelling and I’m too lazy to hit all my abilities correctly.

I recently installed GSE and have got a few macros going with that. I currently have a 103 Feral Druid as DPS (Not sure if I should swap. Been in dungeons with Balance & Guardian druids that hit insane damage compared to me.) and also a 60 WW monk I’m levelling.
Current Macros I’m using on Druid are the ones that come default with GSE. Anyone able to suggest any better ones? I get about 29k DPS which isn’t to great. Would like to be hitting a bit higher but obviously I don’t expect to be hitting with efficiency as if I was doing the abilities manually.

Other than that, is there anything else I should know about Macroing in Legion that may have changed since I last played?
Is it still a viable option to grab a full rotation off a site like IceyVeins and set it up into a full macro like you used to be able to ages ago? Or is that gone now?