Does A Stipulation Of No Court Cases In A Will Effectively Give The Executor The Ability To Take All Of The Inheritance?

TL;DR Does the line "No case shall be brought regarding this will aside from probate." in a Dallas, Texas will give the executor the ability to distribute money as he pleases without potential consequences?

Full Story I am currently considering bringing a suit in Dallas, Texas. To summarize, my grandfather passed leaving a will where he passed down all of his assets "in stirpes" to descendents if any of his three children passed before him. My mother passed, so me and my three siblings were set to inherit 1/12 of the estate each.

However, my uncle was declared as the executor of the estate in the will (he hasn't formally applied through the court), and, based on a conversation with him yesterday (after over a year of him ignoring my requests for information Alane documentation), has interpreted that to mean the money was all given to him to distribute as he pleases, and if I "do God's will" and I obey his every word, he will give me my inheritance (in whatever payments he chooses at his leisure). It sounds like he has already started doing this, giving money to some heirs, but not others, and not in equal shares as dictated by the will.

My hope is that I can bring suit against him for a breach of fiduciary duty. I have asked him for documentation about the administration of the will, but he has given me nothing. I have gotten an Affadavit of heirship (through the county; which was filled out improperly by the executor), the will and trust (which I had to contact his lawyers directly to obtain), and am waiting on the death certificate from the county (which he explicitly told me he wouldn't give me and I would have to go through the county to get it). He has not started probate and does not plan to.

However, my concern is that there is an explicit statement in the will which states: "No case shall be brought regarding this will aside from probate."

So, am I able to start probate and bring a case for breach of fiduciary duty against the executor for the actions listed above? Or does this line in the will effectively let him do as he pleases with the money, as he claims?

If helpful, there is also a line in the will which states that "distributions are to be made within 6 months" of his death, which also did not happen. The executor has also said that if I attempt to file suit against him, he will give me nothing. It is also unclear if any of the accounts owned by my grandfather were beneficiary designated. If they were, I can almost guarantee my mother was listed as a beneficiary, but cannot guarantee that those accounts would have been setup to trickle down to descendents if one of the beneficiaries passed (though they might have; I simply don't know without seeing the accounts).