Macshiny - Installed and paid...is it safe?

It's absolute junk ware and your next step should be to remove from your Mac asap.

Never install any app that claims to "tune up", "speed up" or "clean up" your Mac. These apps exist for one reason: to separate the unwary and inexperienced user from their hard-earned money. At best they do very little, at worst, they can damage your OS installation and cause far more problems than they "solve".

Heavens only knows what this rubbish thought was "dangerous"...

Another pitfall of the app is that MacShiny may scare you by exaggerating the volume of discovered junk and threats in order to make you buy the paid version. On Apple Discussions forum, many users complain that no matter how clean your computer is, the application will most probably show plenty of ‘garbage.’

https://makemacfast.com/macshiny-for-mac/

MacShiny Cons

Annoying ads and pop-ups are included.

Many trustworthy websites and anti-virus solutions deem MacShiny as a malware app.

High prices for the offered quality and features.