Yes, you can upload offline conversions to Facebook. However, it's recommended to use Facebook Conversions API instead of uploading it as an offline event list.

You can track offline conversions on Facebook using the Conversions API. The offline Conversions API is no longer supported, so the Conversions API is your only option to sync offline events with Meta.

Meta Conversions API is free to integrate with Meta. You can set it up by yourself using Meta's documentation. If you don't have coding knowledge and need to hire developers, they might charge heavily for setting up the integration and Conversions API. However, tools like CustomerLabs 1PD Ops offer a free setup for the Conversions API. The only cost you'll be paying is for tracking all the website event data.

To check if your Facebook Conversions API is working, go to your events manager and review the event match quality of server-side events. This will show how effectively the data is being sent through the Conversions API.