Is it sufficient to pour water from a regular jug onto the opening of the penis to cleanse urine without rubbing or squeezing the glans, especially if there is a slight trace of urine on the tissue after wiping?

The cure for obsessive thoughts is to ignore them. What is required in istinja' (cleaning after relieving oneself) is to wash away the impurity until one is reasonably certain it has been removed. Pouring water over the impurity on the private parts is sufficient to purify them. Reasonable certainty is enough; absolute certainty is not required. Therefore, you should pour water over the trace of urine, then get up and do not inspect with tissue or the like.