In D&D 5e, is it at all possible to create half-subclasses? is closed as Too Broad. It's not. It's also not unclear or opinion-based. It could benefit from better wording, especially in the title, but that's not enough that it should be closed right now. Can we reopen it?
I'm not sure
If the question is simply asking Can I homebrew this, then yeah, it's answerable and should be reopened.
If it's asking Can I homebrew this and remain balanced, that's also possibly answerable by someone who has done it, but it also seems to potentially be a shopping question at that point as it's also potentially Has someone done this and can show it to me
If it's asking How do I do this, then that isn't answerable because we don't do "Homebrew this for me".
I think OP needs to clarify what they're looking for so we can determine whether or not to reopen. Of course, I may be wrong on my assessment of the above, but that's my gut reaction and why I originally closed.
Reopened after clarification from OP
OP confirmed in main chat that it is the simple question first listed above. They want to know if it's possible to do it and we can answer that.