I know you said that tape wrapping didn’t fix the build up in your foreskin but I’m uncut too and what works great for me is to tape at least 1,5” from just below the head towards the base of my penis.
I use 2 sections of Johnson & Johnson’s waterproof tape. Each section I cut is 1” wide and about 7.5-8” long. I wrap the first piece of tape right below my glans while pulling the foreskin as far back as I can. I then put the second tape so that it covers the lower 1/4 of the first tape and stick it around my dick, always pulling my foreskin as far back as I can.
I don’t know if this can be of any help for you but it sure works great for me. I pumped 2x15min at 10-12 Hg this morning and didn’t get much of a donut.