Had read about them recently when looking up about bookmarklets:

https://en.wikipedia.org/wiki/Userscript

Which userscript manager do you use? What are your opinions/advice on security of using them?

Also, are there other similar things like bookmarklets and userscripts that regular people can start off fast?

Are there any lemmy communities or resouces(wikis, forums, youtube channels etc) that are on the topic of simple/beginner-friendly automation and customisation?

Thanks in advance