The difference between Japanese verb volitional form and verb goます＋たい

"たい" is called the auxiliary verb of wish, which generally expresses wishes and thoughts. But just thinking about it does not mean taking any action.

The verb is not in the form of う(よう)と思う, expressing the will or determination to take action, so it is not just about talking. When used to express that the conditions for taking action are generally met, it is preparation. An expression of will before performing an act.

So there is a big difference between the two. That is, the occasion used or the mentality when expressed are different.