I’m reading the OP as Swiss claiming the delay was caused by a mechanical issue
(someone will explain better but)...
my understanding is the original text of EU261 didn’t class mechanical issues as non-extraordinary; this has subsequently been challenged in court and now the bulk of mechanical claims are considered non-extraordinary within the EU
Swiss is not an EU carrier and Switzerland is not an EU member state. As such they have made an active choice as a country/organisation to accept EU261 as orginally written, but not any subsequent case law. This means that Swiss (usually) is not on the hook for for compensation for mechanical- it’s not really them flouting the law, it’s just the nature of the unusual arrangement with Switzerland and the EU
i say “usually” because if the flight is from the EU to Switzerland, the regulation applies in full including case law, regardless of the operating headquarters of the airline
on the face of it, if this was ZRH-WAW and was mechanical, I would be managing my expectations and not wasting too much of my time on it