Do I own the copyright to the images I upload?

Yes you can rest assured that your intellectual property rights are not compromised by submitting your copyright images to Adobe Stock.  All you are doing is agreeing to allow Adobe to grant a limited licence to use your work commercially.  I am not a lawyer, but that is my understanding.

Read your Contributor Agreement. If you created the assets that you submitted to Adobe stock, you own the copyright. You retain copyright and can use them in your own projects. Please note, however, that you cannot download your own assets from Adobe Stock even if you have an Adobe Stock subscription. Doing so is considered falsely inflating your sales.