Android developer to integrate apk packaging into gitlab CI/CD

I am looking for an Android developer/DevOps with tons of experiences in packaging Android apps into apk files in a existing gitlab (on premise) CI/CD

Project Details:
- we have from a client existing app sources
- you have to make the apk packaing work in gitlab

MANDATORY
- multiple years of experience with Andorid App Java development
- multiple years of experience with Android Firmware development and packaging for Android
- you can demo us a gitlab environment which is packaging android apps into apk files

The milestones for working:

ms1:
package current sources into apk (manually) and document the required steps

ms2:
implement packaging into gitlab CI/CD


Deliveries?
- in our on premise git (access will be granted to you)
- full sources
- compiling & packaging preferably via docker if custom environment required
- maven or gradle
- preferably JDK 11 or 17

Requirements:
- clean code
- code checked with checkstyle, pmd, spotbugs

Payment?
- you estimate in a WBS after getting the task
- we discuss about clearances and effort
- we mutually agree to effort
- we assign you the task after agree
- you implement & delivery
- we pay
(basically the rules of freelancer)

Closed book vs open book?
We work only on open book.
Closed book means you are unwilling to define a WBS for the work and you add only a price tag to the task. We are sorry we will not hire you in such a case!

budget?
we do not disclose the budget, but we know how much time such a task requires.
Be aware that the person interviewing you in the chat has developer background and thus requires clear technical answers.