I’ve been involved with both Trademarks and Patents for Electronic equipment. Generally, though not always, you register a trademark rather late in the process, though it is not a final step in the development process.
The trademark only applies to the category in which it is applied for, see the other SYNTAKT at the bottom of this post. You register a trademark because it makes it easier to defend, but it is not impossible to defend one without the registration.
History of Trademarks registered by “Elektron Music Machines” with the Swedish Trademark Office:
2021-07-12 SYNTAKT
2020-02-25 Model:Cycles
2018-05-15 Model:Samples
2017-11-30 DIGITAKT
2017-11-07 DIGITONE
2014-08-14 ELEKTRONAUTS
2014-08-14 OVERBRIDGE
2014-01-21 ANALOG KEYS
2014-01-21 ANALOG RYTM
2014-01-21 ANALOG FOUR
2012-10-25 “analog symbol image trademark”
2012-04-16 ELEKTRON
2012-04-16 OCTATRACK
I will leave it to someone else to check the date of release of these products to see how close they come to the trademark dates. ( Notice how the chronology of the DIGITONE and DIGITAKT are switched for trademarking. There is an inside-the-corporation story behind this. )
Another reason you could apply for a trademark would be defensively. This is kind of like grabbing a whole bunch of URL names on the internet, to try to prevent others from using them.
There is an advantage with trademarks though, in that you get to defend them in court, and names that are similar in a same or similar category to other product trademarks are ruled as deceptive trademarks and are taken away. So a synthesizer named DIGITACT by another company would probably not be defensible.
So although Elektron has never filed a defensive trademark in the past, it is very remotely possible that SYNTAKT is one. The SYNTAKT trademark for packaging equipment was filed in the USA about two weeks before ELEKTRON filed their trademark for musical equipment. Perhaps they wanted to defend a name they felt too close to DIGITAKT, but not defensible otherwise, and grabbed it for musical equipment. I really doubt this is the case.
My conclusion is that most likely there is a real product, fairly far along in development, that will eventually have the name SYNTAKT.
BTW: I have some really nice "Elektronaut"stickers and pins that i am selling, before the trademark police catch me. 
