I have the same struggle.
What you can do is try and finish your stories little by little and not force yourself otherwise it WILL become a chore more than a hobby and if you no longer find interest in the ones you’ve already started, you can take a break from them and focus on the new ideas you have. That’s what I did, I unpublished my main project which I have been working on for years, took a break from it in order to focus on the prequel which for now clearly is more interesting for me.
Keep in mind that writing is supposed to be a hobby not something you feel forced to do, so go at your own pace, try writing those ideas down it might help!
But most importantly, no pressure