Relocate roof opening

Hello everyone,

I am new to the forum and glad to get some advice from you.
A brief overview of my project: I have an old building and want to convert the attic.
Currently, there is access from the hallway via a hatch with a retractable ladder. However, this is in the middle of the room. Since I want a fixed wooden staircase for the access, it has to be relocated. Ideally, I would place it above the entrance to the basement.
So:

1. The hatch is about 160 x 100 cm in size. The hatch should be closed in such a way that weight can easily be placed on top. Since the access is in the hallway, I don’t care about impact sound insulation. Later, there will be parquet flooring in the attic. I was thinking either a wooden construction or concrete. The only argument against concrete is that I have no experience with it. For the wooden construction, I was thinking of sturdy wooden blocks laid lengthwise and additionally supported crosswise underneath. Then OSB boards, on the roof chipboard, and in the lower floor a plasterboard ceiling. In between, insulating with rock wool.

2. Access must now be created in a different location. A staircase above the stairway to the basement would be suitable here. The problem is that if I make a ceiling opening here, it would be two stories high. That means cutting out a hole would be difficult, as a roughly 2x1 m hole in concrete would somehow have to be removed... I had thought of drilling a hole every 30 cm continuously and then hammering out a block of 30x30 cm each time.

Do you have any advice for me?

Yes, I have a piece of advice for you: ask a structural engineer. Especially creating a new ceiling opening is a massive intervention in the statics of your house. No one can help you from a distance here. In the worst case, your entire ceiling could collapse at the opening and possibly even tear down a few walls or the whole house with it. That would be too risky for me.