Is there a better one in the price range and I wanted to buy an M.2 SSD and install the operating system there. Does it make it faster and which is better Linux or Windows?
It always depends on what you want to do with it.
Office and surfing.
For the normal user who is not very familiar with Windows, please always.
You won't find anything much better in the price range.
For a "normal consumer" Windows is definitely better (keys start at ~ 5 euro).
And if you only want to use the PC for surfing and office applications, it should be enough. You can't do much more with it anyway.
You should also remember that you only have 64GB available, 16-20GB of which are reserved for Windows, so you only have around 45GB, which is extremely little. You won't get around an additional hard drive, so you should expect an additional ~ 50 euro. A slightly better model may be worthwhile.
Yes, then the fat one is enough