Someone in Canada may be behind false posts about me that have spread internationally. Civil options?

Throwaway because this is a sensitive situation.

I live outside Canada. Recently, an anonymous person published a series of posts about me using my full name, photo and other identifying details. The posts make extremely serious and false allegations about me. From what I can tell, this seems to be a case of mistaken identity.

I’m not going to repeat the allegations here because I don’t want the post to be traceable, but they are the kind of accusations that can seriously damage a person’s reputation, work, family and safety. There has also been at least one explicit violent/death threat.

Since then, the posts have been picked up and shared by a small group of accounts who appear to be trying to push the story and spread more widely. Some of it has now been shared on social media in my own country, so this is no longer just a random post on one site.

It’s honestly been extremely stressful. I’m worried about my reputation, the posts spreading further, and the real-world consequences of having my name and photo tied to allegations like this, even though I deny them completely.

The police in my country have so far advised me to “sit tight” and not engage with the people involved while they assess the matter / before any investigation starts, and just keep documenting. I have also contacted a lawyer here who gave the same advise.

The complicated part: there are strong indications that the anonymous person behind may be in Alberta, Canada, and may possibly be minors. I’m trying to understand what the realistic civil options are before spending money on a lawyer.

Any practical advice from people familiar with cross-border defamation, online harassment, doxxing, or reporting in Alberta/Canada would be appreciated.