I think it might be possible to replace the shift lever with a minimal amount of work. I don’t believe total removal of the shifter cage is required.
In this photo you will see the nut and bolt that attach the shift lever to the linkage piston which is in turn attached to the first U joint.
at the bottom of the shift lever is a ball which glides between two grooved pieces of hardened steel. Please excuse the old, dirty grease.
I think once the nut and bolt are removed you should move the piston rearward. Then, sliding the lever forward should probably provide enough free movement to slide the ball out of the grooved pieces.
Be cautious doing this as the hardened steel pieces are a non-mechanical, loose press-fit into the aluminum housing. Without the ball in place those pieces have the potential to fall out
I would tape thin cardboard, tape or take appropriate steps to prevent losing the nut or bolt should one get away from you in the removal process.
this is not something I’ve done but I’ve played around reassembling the cage and linkage and I think this approach is at least valid for a first, and hopefully successful, approach.