I am a UK citizen looking to visit Canada in the second half of 2024 for a family event.

In 2020 I was arrested and interviewed by the police on serious criminal allegations. Afterwards I was released on conditional bail (which is a status that has to be reviewed and renewed periodically) which expired a month later, and since then I have been 'released under investigation' which is a completely indefinite status that people can remain under for years. No charges have been made at any point and indeed I haven't heard from the police since early 2021.

 - Can I use the eTA system to get authorization to visit Canada?
 - If I can use the eTA system, is my arrest something I would have to disclose, and what documentation would I need to provide? How likely is it that I would be approved?
 - If I can't use the eTA system I would have to apply for a visa – what would be the likelihood of being allowed to visit?

I appreciate this is a vague question which some people might prefer not to answer but any guidance would be very welcome, as the specifics of the criteria aren't the clearest to me and I don't want to embark on a stressful/expensive process if my chances are slim.