Hello vegan2share.
I do not have a urostomy but I am interested in the problems people face with any type of stoma.
Firstly, I would point out that past posts on this subject can be found in 'Collections'>Premium content>General knowledge>urostomy (which is 2nd from last on the list!).
Secondly, I can empathise with you having a problem which not too many others might be sharing and one which the medical profession have little or no idea of how to resolve satisfactorily.
Therefore, we might be in the realm of DIY and experimentation - which is a domain that I am very familiar with for all sorts of different reasons.
As I understand it from your post , one of the problems is urine spouting out whilst you are trying to change catheters/devices. I had a not too dissimilar problem when irrigating my stoma. The way I resolved the problem was to use an irrigation sleeve whilst attending to what needed to be done. After obtaining several samples, the best one that suited my needs was a 2 piece Coloplast irrigation press plate (12820) & Coloplast Assura irrigation sleeves (12836) The press plate also needs a small belt which came with the sample.
What the clear plastic irrigation sleeve does is provide a clear view of the stoma from all directions, at the same time as capturing the output and channelling it into the toilet (or, if I fold and clip it, it will act as a huge temporary bag). The top of the sleeve is open and wide enough to access the stoma area to work on even though there is constant output.
I use the 60mm version because that also gives me room around the stoma to work without causing stress or damage to the delicate tissue.
When finished what I need to do, it is easy to simply remove the sleeve with whatever I have replaced it with firmly in place.
It would be wrong of me to say that this is a no-mess solution, but it is a 'relatively' no-mess set-up in that it prevents the waste from going 'everywhere', as it contains it within the sleeve.
What I have found is that trying lots of different methods is useful to identify more precisely what works and what doesn't in different circumstances.
I hope my short post might prove helpful to you to resolve your particular problem.
Best wishes
Bill