Hi Greg
I don’t do the Instagram thing so don’t know much the expected etiquette (Just googled that and apparently thier are a lot of suggested rules)

We live in a world with a lot of focus on immediate gratification. I.E when we text or such we desire a immediate response and become agitated (making up what if stories) when that desire isn’t met.  But why should that be?

Not that long ago persons in your situation would write letters with weeks in between. The anticipation of receiving a letter can be enjoyable….

In your shoes I might approach the Instagram thing the same way. This will require you to be able to communicate your boundaries.  Let her know you would like to continue communicating with her without the expectation of immediate responses… as if you were writing letters a suitable delay could be agreed on.
And perhaps a promise that if either of you wish to stop the communication you will let each other know. (no ghosting)

In Buddhist terms – What is causing you the headache is your desire and attachment to wanting what you want right now which has very little to do with this woman. She isn’t giving you the headache your are… Imagine enjoying the communications without such attachments.

As a person that tends to live in my head, I get it Greg
The tendency to project my insecurities in to silences between encounters with others… what if they think this or that about me, what if, what if…

Being able to communicate clearly and establishing healthy boundaries can help. Sadly most of us haven’t been taught how to commutate skillfully in such situations.  (just knowing what ones boundaries, making them conscious, is not a easy task.)

Under similar circumstances a philosopher Tom Morris gave me the following advice or rule. The rule of Charity. The rule of Charity states that if you experience a event and thier are multiple possible explanations and you have no way of determining which is the correct explanations or you have decide not to take the time to determine which is the correct explanation then choose the better explanation.

It is possible that this woman is interested in you, enjoys making new acquittances,  likes communicating with people from around the world, pities you, is setting you up for some scam, is a murder looking for the next victim… 🙂
So many what if’s!

You could ask her about each of those possibilities to determine which is true..    or you could choose to pick the most kindest explanation which in this case may be she finds you interesting.

When your not engaged with your insecurities your projecting on the interaction you seem to be  your enjoying the interactions so why can’t that be enough in the present moment? Tomorrow will bring what tomorrow will bring.

As for the question ‘Why do you find it easier to engage with those farther away and or online (virtually) and not closer at hand in the real world… A problem many today have… i
Asking myself that question I might wonder if I find it easier. That a virtual connection that doesn’t work out wont hurt as much as a connection where I actually interacted with the person in the ‘real’ world doesn’t. Especially if I might run into them from time to time. But that’s me