Not able to empty bladder entirely.

Yes, I've had this problem and the urologist had to dilate my urethra tube often. I've always had this small urethra tube and it caused many UTIs. Haven't had it done in years but I need to check it out. Hope you get some relief from this problem!

I have seen advice to people with MS (who often have this problem and the UTIs it leads to) to make a fist with one hand, place it over the bladder - on the outside , obviously! - and the other hand on top of it, and press down with them as the stream of urine slows down. I don't know how well this works at emptying the rest, but it is worth trying.

Sit squarely on the loo , you might need a small step , like the kids use
Make sure your knees are higher than your hips
Lean forward with your elbows on your knees
When the stream stops sit up straight for a minute then go back to elbows on knees

Sit properly on the loo, twist gently from side to side, then lean forward that should help, (that tip is from an Australian urologist physiotherapist)
Also I use a bit of paper pressed against my flue, that helps release urine.
I have Botox once a year in my bladder wall.

I ise the loo with my feet on a small box and bend forward - it feels a bit odd at first but it makes emptying the bladder and bowel a lot easier.

I've been prescribed oestrogen pessaries to help with my frequent uti's caused by having a catheter for two months while in cardiac ICU after heart surgery