I am new to the forum so I'm sorry if I am disobeying any rules. (please let me know if I am) like I said above, I hope I can modify time. for example, I hope I can make sims use the toilet for a very long time instead of using it in an instance like now. If there is already a way, please let me know. I would be very glad If you could help me.

It is but some may be complex.
To start, probably everything in sims 4 is made in "separated actions", for example, a food usually have 5 or 6 'actions' where each one give X amount of hunger, calories, maybe even fun and energy.
Toilets and showers works based on a condition where it will run repeated actions until your need is maxed, the lower the need, the longer it takes. So, basically to answer, you need to search where is the "bladder" and put there a smaller number, just remember to do it to all toilets or some will magically take your pee off faster than the others. (like the city living and any variants)

For most interactions you can find the time in the interactions under the basic_content section labeled as flexible_length (and a few others that can make it exit sooner). For the toilet-use-sitting interaction the main amount of time a sim stays on the toilet is determined by how low the bladder is, and under that section is a time_based with a minimum of 2 sim minutes. So you could attempt to adjust the min_time with a higher number so that no matter what the bladder need is, the sim will be on the toilet for a while longer. Each interaction is different though, just a matter of figuring out what it is using. Make sure to use the TDESCs to help you understand the files.