If you did not have any bowel movement even with all these laxatives, then there are chances of bowel obstruction.
Another possibility is impacted hard stool.
You can try fleet's enema.
If that does not work, please see a gastroenterologist for colonoscopy.
Thank you for all the detail.
Prostate problem is unlikely if your PSA was normal with normal prostate exam.
Normal colonoscopy may likely suggest gastric motility disorder, that is, your colon is not contracting enough to push down the stool.
This may happen with age.
Barium enema will not yield much information adter colonoscopy.
You can consider anorectal manometry to diagnose this condition.
In case, enema does not work, then you may need manual disimpaction.
Nowadays, novel techniques like sacral nerve stimulation is being utilized successfully in selected patients for resistant constipation.