Hi, I'm also Muslim and have been struggling with bathroom trips; I do take longer than I used to, specifically in performing wudhu. I'm certain nobody else takes the precautions that you, me or anyone else struggling may take in the bathroom or anywhere else, no matter what your OCD may make you think. My advice to you would be to force yourself to sit with the 'ickyness' that you may feel. It's essentially at home exposure therapy and works with any thoughts you may have too. You need to force yourself to sit with the uncomfortable, to sit with that feeling and move past it. It helps you to reduce doing that action again in the future as you realise it doesn't matter. Or with thoughts, it makes them appear less significant because you've shown them that they don't have that control over you. The second I did this, is when my OCD drastically reduced. With your specific situation, remember that it's normal to NOT take the precautions that you are taking in the bathroom, and I also recommend that you learn the correct way to perform istinjaa. You naturally need to clean yourself after using the bathroom and it might even be impossible to avoid splashes completely. So, just ensure that once you've finished using the toilet, you clean yourself properly once and in the best way (istinjaa), and then you move on.
Another tip that may help you more generally as well is whenever I'm facing troubling thoughts or feel the urge to do something repeatedly, I tell myself to trust in Allah. Saying those simple words to myself reminds me that there is nothing greater than the trust we should put in Him. My OCD is not greater than my trust in Allah, nothing in this world is. & of course, He sees our struggles, and He knows we are trying. Just remember that these OCD thoughts or 'waswas', are from Shaytaan, so try your best to do what is logical, and then move on. Easier said than done, I know, but remembering Allah often has truly helped me so much more than I could tell you. I hope that by implementing this if you aren't already, you will experience this too.
Wishing you all the best. May Allah ease your struggles and grant you relief from them, ameen!