DSL vs. Fiber Optic Experiences?

Fiber optic is especially much less susceptible to interference. Can't think of a car example right now. Maybe: Copper -> winner of a DTM race, fiber optic winner of Paris Dakar?

Fiber optic is inevitable in a few years. Either you get a discounted installation price now, or you pay significantly more at some point. Copper DSL will be phased out gradually over the next few years; the technology is expensive and energy-intensive, quite unlike passive fiber networks. It might not be about 5 years, but 10 or 15. The mindset should therefore not be about what you "need" now, but something more future-oriented. The fact that ISDN was discontinued is not that long ago, and something similar will happen medium to long term with the thoroughly exhausted copper wires from the industrial revolution era.

Fiber optic is especially inevitable in a few years.

No. Absolutely not. Solely for the reason that even in the medium term, a large part of Germany will not be supplied with it.
Fiber optic usage: currently about 11% of broadband connections
Lack of acceptance: about 75% of the available connections do not use fiber optic at all
Lack of necessity: available copper connections can provide sufficient speed (for private use)

especially since all areas would first have to be equipped with fiber optics. That may now be done as standard in new development areas. But in densely built urban areas where everything is well supplied with copper and cable networks and where the bandwidth demand cannot grow due to lack of space, I do not see that being widespread in 10 years.

So, for me as a dummy to note: Fiber optic is the Ferrari and usually much faster than DSL
Correct?

No, but first to that ...

Just briefly to make sure: By the socket and DSL wiring you really mean the socket where your DSL router plugs in and not a LAN socket where you plug in a PC (where the cable then leads to your router or a switch)

... because that is an absolutely key question for talking past each other, whether in your worldview the plug socket for the end device or the house entry point of the connection is meant.

So, once again very slowly for dummies:
DSL and fiber optic are not alternatives to each other, i.e. there is no "OR" between fiber optic and DSL, because you can get DSL over fiber optic or over copper cable.
The contrasts are therefore not "DSL vs. fiber optic" but "DSL over fiber optic vs. DSL over copper cable".
You are the "subscriber" because you have rented your connection with a permanent contract. The connection is established via a line on which the services are digitally transmitted, together called "Digital Subscriber Line", short DSL.
The difference between copper and fiber optic is that transmission over the metal copper takes place in the form of electrical current, while—as the name fiber optic already says—the "wires" are made of glass. Glass does not conduct electricity, but it conducts light very well. The speed of light is the fastest. That is why you can be offered a fiber optic connection with higher transmission speeds than a metal wire connection.
Of course, a signal transmission morse-coded by a blinker requires a different modem technology than morse-coded by electrical pulses.
However, you have to distinguish several layers of worlds: on the section between your provider and your basement, a different transmission technology can be used than on the section between your basement and your apartment. In between, there is always some technology with switching and translation functions, finally your IAD (Internet Access Device, layman's term "router"), usually something called a "box" (Fritz / Easy / T-Entertain or similar). On the last section (LAN to PC via copper cable, WLAN to tablet via radio) nothing changes if you change the maximum connection speed between provider and basement, which can require simultaneous switching from electrical to light morse, like from bicycle to Ferrari. Not least because wireless light like from the ceiling lamp bulb would not be usable to bring the internet to your tablet, you will usually rely on radio in-house (or copper to the desktop).

[Diese Erläuterung habe ich mir vom Kollegen telthies besorgt.]

since all areas would first have to be equipped with fiber optics. That may now be done as standard in new development areas. But in densely built-up urban areas where everything is well supplied with copper and cable networks and bandwidth demand cannot grow due to lack of space, I do not see that being widespread in 10 years.

For all of Germany, yes. But I can imagine that in the future DSL lines will be discontinued regionally when the provider has already connected the same area via fiber optics. It's basically double costs for hardware/maintenance for the providers. That's exactly what happened at our workplace. We've finally had fiber optics installed and put into operation there for three months. As luck would have it, the provider's DSLAM blew out just last week. It probably won't be fixed anymore because all the buildings in that area are connected via fiber optics.