Bev, learning is hard. Also, Illustrator is somewhat old. Despite it gets improved constantly, some paradigms it uses are 30 years old. It has a lot less functions at the start, and reading a manual was the intended way of learning new stuff. Today it does not always work like that, we always in a hurry, we are pampered with Google and instant search, we want interactivity... Reading the manual still works though :)
Discover panel ties to solve this, but I agree the way it works is still not perfect.

Having 'instant' help on any command/cool/thing in Ai can be useful, I agree. In some older apps, I remember, there was a way to click a Help button, located in the top right corner and click anything to get a help article on it.
Another way to get a short hint on something is to hover and wait long enough — this way it won’t interfere with the workflow when you are familiar with a software enough. This method is harder to discover, but it’s natural.
And Illustrator does hos rich tooltips for tools now, if you hover over a tool icon long enough — but not for every other thing.

To other concerns.

Illustrator can’t guess if a short answer on anything is sufficient specifically for you. It can’t know what your level is. So it gives a full article, and you are free to use any other tool to compress or summarize it to suite your needs, Modern AI-tools (not Ai, but AI) offer a lot of ways to avoid reading. But learning is always hard :) It’s up to you to search, to sieve and reject the parts you don’t need.

Then indeed, if you type in 'stylize' in Discover — it does not provide a separate article on each of existing effects... And the 'Summary of effects' you mentions is not a complete summary and refers to the Photoshop Effects section of the Effect menu... and the only way to get a search function for the article in the Discover panel is to scroll it down until you see a 'Read article in browser'... and the panel does not allow to select a text even. All of these are valid.
Still, the best way to know what each effect does in the Stylize form Illustrator Effects section of the Effect menu — is to try to apply one to an object. Enable preview and play with values.
Again, it does not mean the concerns you raise are bad! It’s just the experimentation is still the best way to learn, and will always be, as we are humans.

Then, the hidden Scissors problem. True, if you have it hidden within the Eraser tool group, Discover won’t show the proper icon, but will highlight the group. Clicking it though will make it active properly — does it for you?
And there is know way to guess if Scissors is in this group, sure. But learning is not guessing, and most of things we learn are not intuitive, since intuition at first is based on a not specific enough knowledge. The more you learn, the more it makes sense for you. Once you learn tools get be grouped, you can learn they are grouped relatively by similarity, they you learn which group has which, then you learn about you can make your own tool panels, then about hidden tools, then you learn you can access them faster with hotkeys, etc.
And honestly, when the team tries to make this process 'easier to learn', with Essentials workspace, hiding some less-used tools, and forcing the previous default, more complex workspace, into non-default Essentials Classic... it gets harder for new users to learn... but this advanced workspace still has Scissors within the Eraser group :)

I wish you all the best. Again, learning is tough. And Illustrator should also learn to become easier to get learned for sure. Compared to modern videogames — a lot.

Hi Egor,
Thank you so much for your genuine answer! It came so fast, I really didn't expect to get a response so promptly so I really appreciate your help.

I did find the 'expand' in the help / discover toolbar as you suggested, but the majority of clickable buttons in any menu is still part of a 'how to...' tutorial' rather than a straightforward answer to 'what is -insert button name-'. Since I'm new to the software, how would I even know what I want to do if I don't know what the tools do??!

E.g. If I want to know what 'Effect' > 'Stylze' (illustrator effect) does, typing 'stylize' in Help will show nothing. I'll have to click again to enter Discover, which I kind of guessed that it's under 'summary of effects'. It's a super long page of text that doesn't allow me to ctrl+f and search 'stylize' and nor does it mention 'stylize'??? (or maybe it does but at this point, I'm already frustrated.) If today I happen to create a shape or something that allows this effect to be used then I'll maybe be able to guess what 'stylize' does, but if not, the software doesn't even tell me why I can't do it...

I spent a lot of time on google just searching why a tool or a button does not work or have no response!

It also bugs me that you can only access the Discover menu after clicking something and not finding it. For instance, if you type 'scissor' to look for the scissors tool in Help, it won't show up right away! By default, this is kind of hidden as you need to toggle the Eraser tool to find it. Who would intuitively think that Eraser is in the same place as a Scissor??

This is the kind of poor ser experience that I'm talking about...

Bev, just recently Adobe introduced Discover panel, available by calling Help > Illustrator Help (or just hitting F1). I tried searching 'expand' — here is how it looks, see the GIF.
I can see where the associated tools and functions are locate (Illustrator highlights them for me when I hover in the app — not shown). Click the first help article, scroll to Expand section — and here you go, it’s written right there: what does Expand do, how it looks.
You can open the page in the browser if you want.

So I have no troubles answering the Expand question. I re-recorded the GIF once, I admit, to make it look better, but the experience was the very same the first time I tried to search 'expand'.

So — have you seen it? Have you tired it? Does it fit your expectations? If not — why and how? I don’t say it’s perfect, and more improvements can be made, so please tell more about it after testing the Discover.