There are a number of good alternatives. Signal wins because it's well known, easy to use and install. Governments are targetting private communications, not a specific app so their entire class is under threat and alternatives that can be backdoored will be.
It's all very short sighted. If you really want to stop private communications you have to outlaw all people with technical knowledge and access to general purpose computers. I can cobble something together that is secure enough for a criminal or terrorist to communicate with freely available software but it won't be full featured or nice to use.
Taken to the extreme this thinking ends with sending all the people with glasses to "work" some fields in the country because intellectuals challenge the security of the regime. That makes no fucking sense in a liberal democracy. So why even start down this path. Get a warrant and surveill people at the end points. It's the only acceptable solution.
Opening up private company communications to the government makes that data a huge target for foreign intelligence and criminal organisations. Even our allies will happily pass on valuable company secrets to their own companies. Everyone is out for themselves. The software our government uses to analyse data will generally be closed source and supplied by a foreign power and not sufficiently audited.
Unfortunately our politicians are dangerously ignorant about the techological risks to national sovereignty and our economy. So they rely on often dubious advice from parties with a vested interest that is opposed to the public interest.