Did you talk to your PCB manufacturer? They may not be able to manufacture this stackup.
Watch these videos. They may help you to understand how PCB is manufactured:https://www.fedevel.com/welldoneblog...r-pcb-is-made/https://www.fedevel.com/welldoneblog...u-should-know/
Drilling has some rules (or better to say - technological limits). Usually, you either drill through hole or you can drill up to certain depth (blind VIA), but then drill diameter is at least as big as the depth (because of plating process - the process when they put copper inside the VIA). If you are building buried VIAs (VIAs which are inside of PCB and you can not see them from outside), they first put together the middle of PCB, drill through it and then they "stick" other layers on top of it.
Also, when you are creating stackup, be aware how much each process cost. You may end up with a stackup which is possible to manufacture but may be much more expensive as if you correct it a little bit.
1) If you use Through hole PCB only, it can cost you 500 USD to manufacture
2) If you use Through hole + uVIAs + Buried VIAs, same size PCB and same number of layers as the Example 1 can cost you 3000 - 5000 USD