Yeah, you can be a good parent and still miss your old life. Also, your previous life wasn’t necessarily “selfish” - what kind of bleak, one-dimensional outlook is this?
You can love your kid, love to spend time with them, and still want to go to that one event, concert, knitting group, cookout, rave party, bike ride, marathon, whatever. Often, you can integrate your kid once they’re old enough, and at other times you’ll have to sacrifice your plans, maybe not getting together with an old friend you haven’t seen in a while. If that makes you feel a little sad and disappointed, that’s called being a human being with nuanced emotions, not being selfish.
Being a good parent is about loving your kid, trying to integrate them, spending quality time with them, all while staying healthy, emotionally balanced and hopefully teaching your kid how to achieve just that.
The parent comment is correct. CODE is the server, you need the “Collabora Online app” for document editing. I’m not aware if there are alternatives to the ownCloud / Nextcloud apps.