Hi. Since I am relatively new contributing to Debian (while doing software development for 3 decades). I thought it might be useful to share a bit of the experience.
One fundamental thing is that you may not be welcomed simply because there is nobody there welcoming you. Adding a merge request for a fix may be pointless, because nobody will merge it. Reviewing is a certain effort and nobody has time for that. This is what I learned when trying to contribute to apache. I had read they might need help and found out there is no way I can help them. Note that I am not complaining, this is just the way it is. It seems you really need to insist a bit if you want to help. I did this with mosquitto and it worked. My experience does however also include other things that worked. I did a successful package salvation for libsml and I did a successful RFS for vzlogger. Sincerely, Joachim