Does the prayer become invalid if the worshiper says: "O Allah, by Your glory, I will perform Umrah" or something similar, and is this considered supplicating to Allah Almighty, knowing that directing such words to a created being might be considered disbelief?

We have not found any statements from the jurists regarding the invalidation of prayer by swearing an oath within it to perform an act of worship. However, we have found their discussions on vowing (making a nadhr) during prayer. They differed on whether prayer is invalidated by uttering a vow intentionally. The correct view is that it does not invalidate the prayer, because it is a communion with Allah, similar to supplication (du'a'). Based on this, when the worshipper says, "O Allah, by Your might, I will certainly perform 'Umrah," it is a communion with Allah, and thus the prayer is not invalidated by it.

However, prayer can be invalidated by lesser things, including expressions that could be interpreted as du'a' if du'a' was not intended. Similarly, prayer is invalidated by uttering some Qur'anic verses if recitation was not intended. So, if one says, "Allah said," their prayer is invalidated because it is purely a statement of information.

The worshipper should not intentionally use these ambiguous formulas during prayer.