Welcome to TRS
After 1985 automatics need computer control
Your 1990 computer can control an A4LD with 2 solenoids, so that's pretty much your choice, rebuild it
The A4LD had more solenoids added in 1995 and was renamed 4R55E, but your older 60-wire computer can't operate it, need the newer 104-wire computer, which would also mean rewiring most of the vehicle
And its not a "better" transmission, just has more shift control based on RPM and engine load, inside its the same transmission
The later model 5R55E was also the same A4LD transmission, but Ford changed the software in the 104-wire computers to add a faux 2nd gear to make shifting smoother
Read here about the A4LD:
https://www.therangerstation.com/tech_library/a4ld.shtml
There are shift kits and other upgrades you can add when rebuilding, depends on what YOU WANT as far as "better performance"
The A4LD was used in Rangers and other "light duty" vehicles from 1985 to 2011, 26 years, just the valve body changed as more solenoids were added, so its a good basic transmission or Ford would have scraped it