Maybe eventually, it has to do with market share and if the service is a “core platform”. Signal doesn’t have enough market share to warrant it yet, even iMessage wasn’t forced to since it’s not that popular in EU. The law was mainly targeted at WhatsApp as that’s THE messenger in the EU.
This is just like Canada banning foreign investment in real estate. It admits there’s a problem, data harvesting , homes as investments, but just solves a small part of the problem pertaining to “foreign bad guys” while ignoring the larger domestic issue.
All it does is make the government look like they did something without actually confronting the powerful interests that are causing the problem.