Use a new building or a 30-year-old house

I am currently considering whether it is worthwhile to build new or rather buy a used house for the following requirements:

[*]120-140 m²
[*]4-5 rooms
[*]Basement
[*]Underfloor heating
[*]Garage

I now have a few properties in mind that meet these requirements and have already undergone some renovation work (e.g., natural gas heating replaced). All are priced around 270,000 - 320,000 euros (house price only, without land for better comparability) and are about 30 years old.

Now my question is: Can the requirements from the list also be reasonably accommodated in a new build, or would that lead to significantly higher costs than with the "used" houses? Apart from the age, what would be the advantage of a new house at all (excluding personal wishes regarding design)? So what has changed in the meantime, which "must-haves" are now standard that did not exist before? To what extent would these justify a premium for a new build?

I hope I was able to express my thoughts somewhat clearly and am already looking forward to your opinions :-)

Hmm, when I look a bit at the usual real estate search engines, even prefabricated houses in that range seem to be significantly more expensive and often don't even have a basement and are anything but turnkey. But I haven't been dealing with it so intensively for very long, maybe I have the wrong impression.

What I also noticed during my research: One of the most interesting things about new buildings is actually a controlled residential ventilation system (as long as it doesn't produce any background noise). Would it be possible to retrofit something like that in 30-year-old houses as well, or should you rather keep your hands off it because, for example, retrofit solutions are rubbish or the houses are generally not sealed tightly enough for such a system (could something be done about that?).