thank you for reaching out to the Wefugees community and your good wishes.
First of all, congratulations that you finished your apprenticeship successfully. Employers try to keep their staff, so in the worst case you will receive short-time allowance which doesn't affect your legal status. If your employer would be finally forced to close down and you lose your job, you won't lose your residence permit, because it is regulated in the law that only offences and a bad-conduct discharge lead to a loss. The conditions for a family reunification are very hard to meet in the case of a §18a residence permit, and therefore you should seek the advice of a lawyer first. You can try to invite someone, but it is at the discretion of the immigration office if your application will be successful. Please note that the immigration offices have postponed any invitation procedures until further notice.
I hope my answers were useful for you and I'll be very pleased if you contact me again with further questions. I'm a member of the MBEON-staff and I‘ll be glad to guide over a longer period of time. Mbeon is an online consultancy for migrants via the mbeon-app, which you can install on your smartphone for free. Download it via App Store or Google Play Store. You'll find me In the mbeon-app under my name „München, Frau Müller“ and get confidential one-to-one advice in a safe virtual room where nobody can wiretap messages. Further information: www.mbeon.de.