A flooding-bot can be pretty intimidating
but even without special tools you can make almost any pc look like a flooding-bot
use the internal sound of your pc as input for your microphone (also works if you have no microphone)
https://www.howtogeek.com/howto/39532/how-to-enable-stereo-mix-in-windows-7-to-record-audio/
record 1 (or more) message(s) with a "bot-like" voice
https://www.naturalreaders.com/online/ (20 minutes per day free use of their premium bot voices)
https://www.wikihow.com/Record-Audio-on-a-PC
mute your browser sound
(because with multiple calls they will not hear your botvoice over all combined their waiting tunes)
https://www.thebalanceeveryday.com/mute-sound-in-your-internet-browser-897051
play the sound recorded on a repeat loop
find a good target right here on scammer.info open op the bobrtc.live page that will connect to your target
set the call to automatic redail
repeat steps 5 and 6 in a new tab untill you have the disered number of outgoing lines you want
this is done is the most basic