Hi @thermokarst and thanks so much for your quick response 
I've first tried to get rid of the noise using the following trunc parameters in DADA2:
--p-trunc-f 157
--p-trunc-r 157
Not entirely sure if this is what you meant, but it does produce only features of lengths >156bp, but running up to 299bp (here's a screenshot of a subset of two samples I'm running just to test this):
If I use any longer trunc-lengths, I remove all my features and nothing is left.
I just came across this thread where you show how to filter out sequences based on length without having to export. I tried this command using '--p-where 'length(sequence) < 160' on the features, which works fine (now I only have ASV's of 157-159 bp), but it just feels like I'm working around the truncation step somehow..
Please let me know your thoughts, I highly appreciate the feedback.
Best regards,
Marcel