Yes, its just between 100 and 200€ of service charge, as they have to unglue and glue back together the machine. And carrying an 27" iMac is also a challenge - you don't want to have it damaged in transport. This all is possible, but it shouldn't be necessary. Didn't stop me from buying and loving my iMac, but it is not good design.
I am planning to get a Mac Studio as the replacement for that iMac, but I would be happier, if easy cleaning of the fans would be possible.