A free CAD type program may be your best option, although the reference to free is not a requirement noted in your question.
One program free for hobbyists is Fusion 360, but it's quite complex to learn. There are many YouTube tutorials and commercial video productions to support the program, reducing the challenge of learning such a powerful piece of software.
Another program, also free and somewhat less complex is Solvespace. Both programs work on the premise of creating sketches in a plane, adding constraints (or not) and allowing three dimensional viewing and editing of those sketches.
There are other similar programs but the two referenced above are those in which I have some experience and believe will serve your purposes.
As you do not require many of the complex features of Fusion 360, I suggest that Solvespace will provide for your requirements with the shortest learning curve. Consider to view a few tutorial videos for this program to assist in your decision.