What is Reddit's opinion of CASIO FX-991EX Advanced Engineering/Scientific Calculator (UK Version), Black?

From 3.5 billion Reddit comments

I never used a graphing calculator - this (about £20 on Amazon) was the calculator that basically everybody in my class had. If you really wanted to have something in a graph form you'd just use Desmos etc

get this calculator for £30 as it can do all quadratics, that question and tonnes of other things getting you an easy 15-20 marks throughout all the papers. plus you need it if your gonna do a level.

https://www.amazon.co.uk/FX-991EX-Advanced-Scientific-Calculator-VERSION/dp/B0719FWP3X/ref=pd\_lpo\_3?pd\_rd\_i=B0719FWP3X&psc=1

Our physics teacher specifically instructed the invigilators for mocks to not allow them, although he is hardly the best source for information.

I think the data bank regulation actually means data you can input and store yourself, meaning you could have revision notes stored on there, rather than just constants.

The amazon listing states that the calculator is "Approved for Key stages 3, 4 and 5, recommended for Advanced GCSE, A/AS level and Highers. Allowed in every UK exam where a calculator can be used."

Seems fairly clear cut to me but the whole situation is a mess. For example, if asked to solve a quadratic equation, do you still have to do it manually and use the calculator to check? Or can you just straight up write down the solutions it gives you? Simultaneous equations? Matrix multiplication?

I am unsure where else to ask this as it is so specific to math. If you have a better sub I would greatly appreciate the guidance! My stepson is starting high school and I want to get him a good calculator, I have found a few but I would love if I could get some advice on what you would prefer in one? It will be used in exams for 5-6 years so I want it to age well and for him to know how to use it in the future. The school won't tell you what to get until literally the first day and as you can imagine they will sell out by then ugh.
This is what I have narrowed down:
1. https://smile.amazon.co.uk/dp/B0719FWP3X/
2. https://smile.amazon.co.uk/dp/B082FT7L5B/
3. https://smile.amazon.co.uk/dp/B07J65SZ46/
4. https://smile.amazon.co.uk/dp/B07L68RQCX/

https://www.amazon.co.uk/FX-991EX-Advanced-Scientific-Calculator-VERSION/dp/B0719FWP3X/ref=asc_df_B0719FWP3X/?tag=googshopuk-21&linkCode=df0&hvadid=232043158271&hvpos=&hvnetw=g&hvrand=7567147271450208441&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9045625&hvtargid=pla-351228833411&psc=1&th=1&psc=1

You can’t, you’ll need something like this

 

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A-Level Maths needs one of these. Not graphical but that's what I was told