Damn silly thing to have on a single handed cruising boat, ranks alongside running backstays and a bendy mast.
That explains a lot and would certainly at least in part explain why your boat has such a narrow wind range for its sails.
Obviously, we have different approaches to sailing. While I absolutely agree that running backstays are not appropriate on a single-handed cruising boat, (which is one of my objections to cutter rigs that need runners opposing the staysail in heavier air), an easily adjustable backstay and a mast that can be bent a little seems like critical tools to me.
In my view of sailing, saying that a "bendable mast and an adjustable backstay does not belong on a single-handed cruising boat" (or at least on a fractional rig without in-mast furling) is just like saying that "a furlable genoa or a first reef does not belong on a single-handed cruising boat." I say that because properly used, using the full range of backstay adjustment results in the same reduction in heel, leeway, and weather helm as partially furling the genoa and putting in a first reef. In my current boat, the entire range of adjustment for the backstay menas pulling in roughly 6 feet of line, that does not need a winch, that is accessible from the helm, and its under a lot less load than either a reef line or the line for my furler.
Perhaps it would be helpful to someone reading this discussion, if you can explain why you think a bendable spar, or a backstay adjuster is not suited for a single-handed cruising boat since they have been the norm for quite for at least 2-3 decades now on well built distance cruisers.