Update;
I solved the case. I am not fully aware how things works but seems like problem arised because of railway having two version(I cannot think better word) of private and public network for DB and to create the first connection before web-hosting one must use the public(note: They default provide a private and there is no reference to such a difference exist. So there were no posibility for me to understand that.) I learned that after a friend of mine suggested me to contact railway and ask them the issiue as well . They responded 3 days later and told me that ı have to go for some settings and find public network and get the db settings from the first and when ı do launch then ı change it to private. Don ask me why and how. That is what they told me to do and ı did it. Then voila! suddenly ı connect. Of course all tables and data is gone.(I believe could be expected but ı am curious if it persists if ı go back to sqlite). All users even superuser is gone as well. I am not sure if ı can create superuser with same info again but ı am too tired to check now.
So yea! Thank you for your time and support :):):)