soldering is easy, it’s the whole de-soldering thing you need to be proficient at - people do this, i tried but didn’t have the right kit to desolder - you should be able to find the dual-potentiometer model on here with a bit of google-foo … but it would make more sense to ask Elektron if they have the serial tracked at sales or at registration (presumably you didn’t) and also to get the right part number and advice
these pots are potentially noisy, there should be some filtering of this but it might help to rotate full CW / CCW a load of times and press the button in too - just give the pot a bit of a workout - this might help if you are lucky, and it’s not borked
it’s hard to know if you experience noisy false triggering of activity or wild fluctuations
don’t be tempted to clean with anything without doing full due diligence on how that can play out badly - again, ask elektron about all of the above, you may find you are covered and then the details don’t matter
You shouldn’t need a receipt to get it repaired. Elektron should be able to use your DN’s serial number to determine whether it’s still under warranty.
Especially if it’s been less than 2 years since your DN was built. To that end, it should also have the year and week of manufacture printed on the back.
Also, if you bought it at a local shop, you might want to call them and see if they have a record of the sale. Since it was less than 2 years ago, they probably do.
And if you bought it with a credit card, it will of course be on your statement.