Inherited property with a prefabricated house built in 1978 - what now?

Location is included in the standard land value. I don't find the existing basement nearly as positive as 11ant does. First of all, it has to be in a usable condition, and the staircase location and the dimensions in general can also be perceived as limitations. It's not just the exterior dimensions that are affected; load-bearing walls inside at best align with each other, otherwise the structural engineer has to resort to tricks (=money).

I would leave out the real estate agent. Useless. The bidders are already lining up, what could the agent possibly contribute.

The question arises as to how the individual points can be evaluated. Perhaps the disposal balances out with the basement and the garage.

Value is, as they say in Cologne, what a fool will pay for it. In this respect, leave it to the interested parties to decide whether and how strongly they perceive a mutual balancing. For you, "the only way is up" applies.

I gladly accept the objection that the existing basement does not have the hair or eye color the buyer dreams of. But if someone suspects an even more beautiful princess elsewhere, they don’t have to bid or can drop out earlier.

As a seller, one may realistically like to be, but one does not need to be objective: you are a party and have a selfish interest. The buyer will state for themselves if it seems worth less to them.