Breakthrough through the floor

I have been following along here for a while but haven't written anything so far, so: Hello everyone!

I have a quick question, which probably isn't so easy to answer. But that's okay. A rough approach is enough for me.

So: I am currently planning to buy a bungalow built in 1995 with a basement. Everything is fine with the house so far, but what is missing is a direct basement access from the apartment downstairs. So you have to go "outside." However, this is a dealbreaker. So my idea is: simply cut out a piece of floor on the ground floor and install a staircase down. The real estate agent cannot tell me what the floor is made of but suspects concrete.

Does this first floor have a specific (construction) name?
Can it be made of something other than concrete?
And is a roughly 2x1 m breakthrough even possible here? Does this have to be done by a specialist company or can any mason do it with an angle grinder?

Many thanks for your answers!

Something like this can and should only be done together with a structural engineer. Anything else would be unprofessional and dangerous.

I have been reading here for a while,

Then you surely also know that the forum rules have changed since your registration. Please enter your profession as well as your construction site! Thank you + Rhineland greetings