New IKEA kitchen - Questions before assembly - Are replacement parts in stock?

I have dealt with shipping companies where there were transport damages with almost every delivery. Do you have to meticulously document visible damages to packages at IKEA, or is this uncommon due to the high number of packages, and you just sort it out later calmly with the IKEA hotline?
Can you also get the necessary replacement items on short notice and if necessary from different furniture stores, or do you have to wait longer for a re-delivery from the central warehouse?

Everything was fine for us, IKEA has always been accommodating in this regard. (I even once had a side cut which was caused by incorrect advice, that was replaced as well)
In our store, fittings or similar items were always available. But that is certainly unplannable.

I am getting several electrical devices from IKEA and am wondering how they are supposed to be connected (for example, Schuko plug, open cable ends, only connection terminals, etc.)? The devices are the built-in dishwasher RENGÖRA, the convection oven ANRÄTTA, and the ceramic cooktop MATMÄSSIG. Depending on the type of connection, I might need to make some changes to the electrical installation (e.g., install sockets). For the cooktop, I would almost exclude a factory Schuko plug since according to the instructions it can be connected with multiple phases. Nevertheless, I would like to know in advance how the devices are connected, what connection cables are provided, and how long these are?

I don’t know about the convection oven. The cooktop came without a Schuko plug, only a cable. The cable end was long enough to be routed to a nearby individually fused socket. All other devices had Schuko plugs.

How much effort is required later to access built-in electrical appliances like the dishwasher or oven? For the dishwasher, I assume it is simply slid in precisely and the cabinet door is then attached to the dishwasher door. For the oven, however, I somehow can’t imagine how it is fastened in the existing cabinet or what exactly needs to be dismantled to pull the oven out of the kitchen unit?

According to the instructions, the dishwasher is slid in last; next time I would put it in earlier. Otherwise it was like you described.
The oven was (for us) slid in and screwed tight from the front with 4 screws.
The refrigerator was more difficult to install and align because of its heavy weight.

Once and never again...

Better to buy somewhere else where the assembly is affordable.
In combination with assembly, the IKEA kitchen is no longer that cheap.

Ikea kitchen is qualitatively okay, the assembly affordable, ours cost all incl. 4500,- ready in the house. The oven has a Schuko plug. Ours is now one and the Ikea no name appliances are not as bad as feared, the oven even really good. The microwave top. I use it a lot.

Structure affordable? I see it differently.

In combination with assembly, the Ikea kitchen is no longer so cheap

We have currently obtained prices from various kitchen studios and with almost identical planning, the fully assembled IKEA kitchen with the same appliances costs not even 75% of the studio prices. So the assembly is not terribly expensive. We still assemble it ourselves, saving another 2k. And by the way, this is in Lower Saxony, I could imagine that the conditions in more expensive regions are even more extreme due to presumably higher studio prices…

We have an L-shaped kitchen about 4m something with wall cabinets, appliances, wall panels, LED lighting, extractor hood. Assembly 800 something. Is that already too expensive for you?