Meta has recommended a few specific steps in order to allow pixels to track anonymous users in this article on Meta's website, summarized in this article as well.
Step 1: Verify your domain
One change coming in Facebook will be a limit of 8 conversion events for optimization and reporting. Verifying your business with Domain Verification in Facebook will allow you to control which events are used.
There are other advantages to Domain Verification, including some settings that are only available after verification is complete.
Step 2: Prioritize 8 conversion events to use.
Using Aggregated Events Measurement in Facebook Events Manager, you'll be able to set the event priority of up to 8 standard events and custom conversions.
This will allow these 8 events to gather data on events even from customers that have cross-site tracking protections. To use your Octane AI custom events with this feature, you'll have to create custom conversions for them first.
For a full list of changes and best practices, check out this article from Facebook.