Slow animations/graphics after waking from sleep

Product:

Model Name: MacBook Pro

Model Identifier: MacBookPro11,4

Processor Name: Intel Core i7

Processor Speed: 2,2 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 6 MB

Memory: 16 GB

Boot ROM Version: 187.0.0.0.0

Mac OS:

10.14.1

Description:

I've had this problem for a long time now (since Sierra). Sometimes, seemingly at random, after my MacBook wakes from sleep, the animations are sluggish and slow (e.g., transitioning to another workspace; minimizing/maximizing applications; F4 to show installed applications).

I haven't recognised any pattern to this behaviour. Sometimes I'll use my Mac for a couple of weeks without it happening, and other times it happens right after every restart/sleep cycle. For example, today I installed the latest update v10.14.1 and everything was fine after the update. Then I closed the lid and went for lunch and came back. After opening the lid I was experiencing this problem and it has persisted all day, even after sleeping the Mac twice for about 30min during the afternoon.

This is incredibly tiresome since it seems to only be fixed by restarting the Mac. Not only this, but this isn't the performance and smoothness I'd expect from an Apple device... (for example, scrolling this page as I write this report in Safari v12.0.1 is extremely sluggish).

Troubleshooting steps:

I haven't done any, I've read many different reports of similar problems but no one ever found a solution it

EDIT: overall the performance of CPU bound tasks like running applications, compiling, Docker containers, all seem to retain the same performance. This seems to affect anything regarding graphics (even vim inside iTerm2).