Were they all on your application?

Pretty sure it asked if you have ever failed a check ride I put Yes
Then it asked what Checkride and I had put CSE and CFII didnt think it was asking for every single time I had failed a CSE Checkride.

On trying to start a new application with the air carrier it didn’t ask for Checkride failures just says have you ever failed a Checkride and I put yes on it. No explanation or anything asked on there.

No. You were never hired, and you never went to training. You were extended a conditional offer, meaning a tentative offer. One cannot say if you will ever know; that depends on the employer, but most likely tomorrow they won't remember your name. They've moved on and see thousands of applications. They're not in the least concerned that you know why you weren't hired. You can ask, but whether you'll ever hear back is only something to be determined by that prospective employer. The HR record used in the hiring process isn't part of the PRD if you never worked for the employer. You were never an employee there, thus there is no requirement to submit that data to the PRD.

When you say "CSE," do you mean "commercial, single-engine?" You say you told the employer about two commercial failures but missed one? Failed the commercial three times?

If you read the thread, PRIA ends, PRD begins.

Unless your employer wrote down the specifics of each training failure, chances are what they saw and heard was simply, "I had a training failure." If you missed one when you described your history, then it's easily explained later, if you're given the chance. On the other hand, if you've had enough training failures that one is easily missed, that could be a problem, too.

When an application asks if you've ever had (fill in your favorite issue), then the word "ever" generally means the plain-English rendering: since recorded history began. Since the start of your lifetime. Since the big bang. Ever.

If the employer wanted to know a specific period of time, there's a good chance that the employer would have so-stated; have you had, in the last five years, for example.