I think what I would do is go with the original plan with modifications. I have a lathe, so that tool greatly influences my thinking. Find a friend or local machine shop and with a piece of 4130 rod, machine, drill and tap a plug that could be inserted into the lift strut after cutting out the existing fitting. By careful measurement and machining, a bit of the strut tube could be sacrificed for ease of removal of the existing threaded rod end and the plug machined to allow exact required dimensions for welding in place.