From the documentation: for JMS topics, the VSE service takes the place of the live service during playback. You must shut down the live service so that it does not interfere with the handling of requests. Live invocation mode is not supported. The virtual service model that is generated does not include a passthrough step.
So, every request published by the client will be picked up by the virtual service. You cannot filter BEFORE the Listen step. A functional VSE is limited to 10 transactions/second throughput. The decreased performance of the VSE might be due to the 10 tps throttling. The performance degradation is NOT because of the "No Match Found"
The Request Data Manager DPH should work, if you use Keep-actions it allows you to reduce your signature to the base minimum of arguments that you need to select the correct answer for the incoming request. If you continue to get "No Match Found" then you're adapted incoming request resulting from the DPH in the Listen step is not in sync with the signatures in your VSI.
You either need to post some screenshots from the Portal's inspection view together with your vsi signatures.
Or alternatively, if you open an support issue then someone can have a look during a webex.
Cheers,
Danny