HP23 constant memory occupation increase

That’s true, you can’t restore it. You can only restore by re-adding the device

Hmm, isn’t it auto-recrecreated?

Not sure, I’ve never needed to remove an Insights log myself.

It is, after Homey receives new values. At least, that is my experience when I accidentally deleted an Insight.

I can confirm. Removing/deleting Insights does’t help at all in terms of ram usage. And Items removed come back as soon as new values are received.