Yes, someone who know noting about bitcoin can invest in bitcoin either through a third party institution or from a close friend who is into bitcoin investment. However, I wont advise anyone to invest through any third party because you wont have full custody of your bitcoin. A good reason why third party is not advise is due to trust issues. People can change, your relative, friend or close one can steal your asset or refuse to give you access to it, after you have accumulated a lot of bitcoin. My 2 cent here is that you try as much as possible to learn how to buy and how to secure your bitcoin. Both will give you a quick start to understanding how bitcoin works.
Yeah I share similar thoughts with you on answering the OP, yes it’s important to have good knowledge of the business or investment you’re about to get into to avoid losses and other mistakes and errors. But I think with bitcoin it can be a little Bit different as it’s not like the traditional businesses or ventures.
Just like you’ve said someone can do it for you, just you provide the funds but it’s not without its disadvantages doing this.
And I’ll not advise someone to invest in bitcoin when you don’t know shit about it.