Dear @moejojo
The only option available to you is 19d. As you have a Duldung, you cannot be issued with a permit like 18b without leaving the country. You could return to your home country and apply for a visa to re-enter Germany for work. If you wish to stay in Germany, you first have to take 19d. People with 19d can only bring their spouse to Germany if they were already married when the permit is issued. The authorities have some discretion in this and so your partner can still make a visa application at the German embassy once you have been issued with 19d.
Family reunification is easier with 18b. I have not found any clear guideline on how long a person has to have 19d before being able to switch to another permit such as 18b. You could apply for 18b once you are issued with 19d. The authorities may first tell you to complete the probation period of your job (Probezeit), or they may issue you with 19d for a year and then enable you to switch. It would be worth your while requesting 18b and if they reject it, seeing on what legal grounds they do so.
Best,
Éanna