I'd say reset the linkage again. With the rods off and tabs on, I cycle each shift fork through the gear positions and return to neutral. The shifter gate centered with the pin. The rods should slip in without effort.
You may still need to tune the adjustment to compensate for any wear, one rod at a time, one pivot revolution at a time, and test run. Remember where you start.
Make sure your shifter is cleaned and lubed. Sometimes they just need to be rebuilt.
