Can I spend additional ki points to make additional attacks with my Flurry of Blows bonus action?

Question

I just re-read the rules about monks and I wonder how to interpret this from the PHB:

Immediately after you take the Attack action on your turn, you can spend 1 ki point to make two unarmed strikes as a bonus action.

Can you spend additional ki points to make additional attacks as part of the Flurry of Blows bonus action, e.g. 2 ki points to make four attacks with your bonus action?

Answer 1

You can make one flurry with two strikes

Flurry of Blows is not limited by a number per turn, but by coupling it to taking the Attack action on your turn, and by your available bonus actions:

Immediately after you take the Attack action on your turn, you can spend 1 ki point to make two unarmed strikes as a bonus action.

So, if for example you have a multiclass fighter/monk who has Action Surge, they can use it to take a second Attack action in the same turn. However, since Flurry of Blows is a bonus action, you still cannot make multiple Flurry of Blows, because you normally only have one bonus action per turn, and Action Surge only gives you an additional action, not also an additional bonus action. p. 189 PHB:

You can take only one bonus action on your turn, so you must choose which bonus action to use when you have more than one available

It also only allows you to spend one ki to make two unarmed strikes as a bonus action. There is nothing in there that says you can spend 2 ki to make four attacks as a bonus action, or 3 ki to make six attacks. It would need to say something like "For every ki point you spend, you can make to additional attacks; all these attacks are made as your bonus action". It does not say anything like that.

Answer 2

You only have one bonus action per turn

Flurry of Blows uses your bonus action so even if you could take the Attack action twice per turn, you would still only be allowed to use Flurry of Blows once as you only get one bonus action per turn and as far as I know there are no means to get more of them.

Regarding your second question, the wording to me implies that "immediately after you take Attack action is meant to apply to both spending the ki point and making the unarmed strikes so strictly reading the rules no movement would be possible, you're spending the point and making the strikes at the same time, there's no interval between them:

Immediately after you take the Attack action on your turn, you can spend 1 ki point to make two unarmed strikes as a bonus action.

I tend to not be very strict though so if a player asked this at my table I would allow them to move in between but wouldn't allow to do anything else.