Trained with The Starting Strength program (3) days per week and progressed for about a year. Switched to 4 days and continued progressing.
Eventually moved to the 531 program to continue LP. (About 1 year). Progress is at a grinding halt lately. Thoughts on what benefits there would be to switching program. Which program?

Male, 58 years old, 5’4, 168lbs
Deadlift 322lb x 5
Squat 297 x 5
Press 145 x5
Bench 195 x 5