It will improve on a weekly basis.

Instead of diving into a hiit set that is too taxing on the heart, try something easier first.

When the body and heart get used to it, then try harder than last time, you will see the bpm at max and rest gradually drop.

Well if you are feeling comfortable, then it is fine.

Though it really does depend on intensity. A 10/10 effort (trying to break previous record) will spike your HR a lot more than regular.

But yeah, the chart looks ok, kipidab