Hi,
First, yes, PRs are always welcome and a sign that you can make changes in the code base that lead towards your goal.
Please note that while the git repo still has the latest version of the code, we are preparing to move the Modbat project to gitlab:
So we will use that issue tracker. I will soon put a corresponding notice on the old github repo.
You are always welcome to share a draft proposal with us. Please share it at least two days before the deadline so we still have time to respond.