I do my own variation of 531. At first, W531 helped me gain a decent amount of strength, but the volume was not enough.
What I do now:
Week 1- 5x5
Week 2- 5x3
Week 3- Find Max
Week 4- 5x5
Week 5- 5x3
Week 6- Deload
The last day of each week has accessory work, i.e. Weighted Dips, BSS, Floor Press, L Sits, etc.
The biggest thing that has helped me gain strength is eating more. I compete in sports with weight classes, so I just increased gradually with milk.
Try to troubleshoot your W531 before switching it up.