GNURadio -- Beginner's questions

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The discussion focuses on using GNURadio on a Raspberry Pi 5 to process audio from online radio receivers like WebSDR and KiwiSDR. The user initially faced issues with connecting the audio output from the receiver's web page to an "Audio Source" block in GNURadio, encountering errors related to type mismatches and missing audio sources. After troubleshooting, they discovered that the error stemmed from using the internal system name instead of the alias name created in asound.conf for the monitor source. Once the correct alias was used, the problem was resolved, allowing the flow to run successfully. This highlights the importance of proper configuration in audio source connections within GNURadio.
Swamp Thing
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I would like to experiment with GNURadio (https://www.gnuradio.org/) to process the audio that I can hear from online radio receivers (with web interfaces) like WebSDR and KiwiSDR. I have a couple of questions.

General question: I have installed GNURadio on my Raspberry Pi 5. Would it be fast enough to process audio frequency inputs in real time to decode digital modulation with bandwidths of 1 or 2 khz?

Specific Question: I want to pipe the output that I can hear on the receiver's web page, to an "Audio Source" block in GNURadio. I have tried following these instructions:
1) https://stackoverflow.com/questions/32213443/gnu-radio-use-sound-output-as-input-source
2) https://wiki.archlinux.org/title/PulseAudio/Examples#ALSA_monitor_source

I can now see "Monitor of Bluetooth Headphones" in the PulseAudio volume control, and I can see it listed as a monitor when I run pactl list. I have entered its name (which is bluez_output.A2_10_10_A1_3A_5F.1.monitor) into the "Name" field in the Audio Source Block. However, the block's output pin and the connection wire are shown in red (which I understand indicates an error). The "Run" button is greyed out.

How can I fix this problem with the Audio Source?

====== UPDATE ======

I just found that there is a red "x" button that opens an error window. The error was that I was trying to wire a "float" type source into a "complex" block. After inserting a float-to-complex converter, I can now run the flow. But I have a new issue:

Code:
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM bluez_output.A2_10_10_A1_3A_5F.1.monitor
audio_alsa_source :error: [bluez_output.A2_10_10_A1_3A_5F.1.monitor]: No such file or directory

==== UPDATE - 2 ====
Problem solved: You have to put in the monitor source's alias name that you create in asound.conf, as per the two links in my question. Silly me, I put in the internal system name rather than the alias of the monitor source.
 
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