Dna Revealed That My Late Father Wasn’t My Biological Father. Legal Ramifications?

My “father” died years ago and did not have a will. The probate court (Texas, United States) issued a Judgment Declaring Heirship, and his other children (my half siblings) and I jointly inherited some land. We later sold a portion of land, and I received cash from the sale. We also still jointly own the remainder of the land. Now, years later, Ancestry DNA has revealed that he was almost definitely not my biological father. I’m well into adulthood, my paternity was never questioned, and I never suspected anything. He and my mother were married before and after my conception and birth. A different man appears to have been my biological father (based on multiple DNA relative matches), and he is still living. We’ve been in touch and are currently waiting on his Ancestry DNA results, which will likely confirm.

My “half siblings” from the father who raised me do not have any affection for me and were not kind during the estate proceedings. There’s not any bad blood per se, but there’s a large age gap and no real relationship between them and our late father, whereas I was close to him. For them it was a business transaction. I think it’s very possible they will come after me legally once they learn I was not his biological child. I have read that a Judgment Declaring Heirship can be appealed based on fraud (which this probably wasn’t) or mistake of fact (which this probably was). I’m doing research and have reached out to multiple attorneys, but I’m having trouble getting attorneys to reply. Several have told me my situation is unprecedented (in their experience). Anyone have any helpful info?