The shifter may be loose because of a worn-out shift tube, bushings, or linkage.
Here are some things to check:
Shift tube – The plastic bushings on the shift tube can wear out, making the shifter feel loose.
Shift cable – If the cable is stretched or damaged, it may not shift properly.
Bolts on the steering column – Sometimes, the bolts holding the shifter get loose. Tightening them may help.
Linkage under the truck – Check if the linkage near the transmission is worn or loose.
If the shifter is still sloppy after checking these, you may need to replace the shift tube or bushings.