I think the key thing is to go after their sources of funding. The radicals get funding from Soros and various foundations. The radicals on the streets are just pawns for the elites. As long as elites are able to provide funding, there will be an endless supply of radicals.
It's like with terrorism. As long as there is funding, and a training base which uses that funding to turn out radicals, there will be an endless supply of terrorists, drawing us into a futile game of whack-a-mole.
The key is to identify the sources of funding, and go after THEM. No matter how wealthy, powerful, or "respectable", go after the funding sources.
One step would be to terminate government "research" grants going to radical professors. We do not need to fund research into "transgender influences in the music industry". Just cut out all those grants.
A next step is to roll up the people who organize and fund the "Black Bloc" groups, the BLM groups, etc. Use the laws that were used to go after the Klan, and make them liable for the actions of the groups they give funding and support to.
Yes, the government has been funding the radical left for decades.
Funding is an important facet. Reform of non-profits is another way to reduce the funding.
Shining a light on who funds what helps reduce support for the violent groups.
We have plenty of laws to use. It is not hard to infiltrate these groups, and they are using the Internet and Cell phone system to organize.