Flameshot is the Linux Screenshot Tool you may have been longing for
A triumph for Arch Linux distros as this app is already in AUR ready to click-and-install (whilst there is an availability issue for Ubuntu apparently). But that said, there is always Shutter (http://shutter-project.org/), which I used for many years on Linux Mint, which also has drawing and pixelating functions if I recall correctly. The default screen capture tool on Majaro Linux (Spectacle) does not have the drawing features and I do not actually like the way it first clicks before it starts to select.
So I'll be comparing Flameshot and Shutter for my own and see which one I'll go for.