How to cluster sequences into OTUs, not ASV

Hello!

One can use vsearch-dereplicate plugin within Qiime2 to dereplicate demultiplexed sequences, which results in feature table and representative sequences artifacts. Those can be used for chimera detection and clustering into OTUs at desired threshold. It skips Dada2, so you can use it for the metrics you mentioned above. You can check this thread for an example how to replicate sequences.

Does it help?