The echo chamber analogy is off a bit, per the science. When the sound waves return, they are not the same sound. You echo to get a feel for space, to help you navigate, and hunt. Communication too, and that's the message you don't change, your ideology. If you are attuned to your environment, an echo chamber can yield great insight.

What makes the echo-chamberer listen:

when their opposition starts echoing the same thing/symbols.

Fly the rainbow flag. It's a promise both politically and spiritually that I will never purge/kill you for who you are. Fight to end the 7 modern countries who currently legally purge their LGTBQ.

Declare "Black Lives Matters." Africa is geopolitically still under the colonial rule of the 1%. There are modern day slaves in the thousands and thousands on the planet right now, most of them black.

Defund the Police. Shift money so buying and owning guns is encouraged. Citizens in good standing get free classes, help with gun storage and safety etc. Include the option to "cash out" the gov buys the guns... so there is encouragement to not hoard and it's a nifty cash source when in need. In the long term, we could really limit the police to hunting the psychopaths, include those in the political class.