Whichever provider you choose, make sure you test delivery before you blast them. Create a bunch of emails yourself at different providers and check if the service you are testing is successfully delivering without emails ending up in spam and how do delivered emails look. You can decide on which to test by counting the most common domains on your list. With 2k emails, I don’t see why using Gmail and a custom domain as a sender wouldn’t work, you just split it up in several batches. You’ll need to take care of your own tracking though as Gmail will give you none. If that is an issue, you should pick a professional provider.