Merlin and eBird are linked. You should be able to log into eBird using the same username or email address and password. I would suggest doing this on the web, because the website has a lot more options than the eBird app (but the app is great for when you’re out birding!)
Then you can export your data from eBird. Here’s some info about how to do that: https://support.ebird.org/en/support/solutions/articles/48000794682-my-ebird
I now only track my sightings in eBird. When I get a new species, it shows up on my Merlin life list as well, which is handy for field identification. While eBird can be a little intimidating to start using, they have some good tutorials online, and the data you submit contributes to real research, which is awesome.