They would have had about 1:15 to score a TD had they not gotten the onsides. Plus if you recover the onsides after the fg you have 2:35 to score and a time out and two minute warning
But again i point out that they ended up kicking a fg anyway. So in what is admittedly an insignificant sample size, i am correct in that they sjoild have kicked it with 2:40 left
none of the probabilities are great but banking on a td AND onsides is the worst
You are 100%, beyond a shadow of a doubt incorrect. This is not a simple matter of opinion. When you are still on that first drive, down 10, you simply do not end a drive prematurely by kicking the FG on anything less than 4th down. You take your shots, knowing you have a shot at the TD you must have.
First, you don't know ahead of time if on that first drive going from 1st down at the GB 25 is going to take 6 seconds, 15 seconds, 30 seconds, etc., to get the TD. What you do know is kicking the FG early is then going to leave you in the position of having to get the TD the next time. It means you're gonna have to get that extra 40+ yards on the drive where the defense knows you have to get the TD. That makes it easier for the defense and harder on your offense.
You have a kicker who has a career long of 62 yards, so that means you can reasonably give it a shot from the GB 44. So, if you get the TD first, you then only need to get to the GB 44 to have a decent chance to tie. GB knows this, too, so their defense has more pressure. They don't want to lose the game on a big pass play, but they also can't be too conservative or they'll make giving up the FG too easy.
Dallas had the ball with a 1st down on the GB 15 with 2:06 left. Since you don't get to use hindsight in an analysis on what was the right decision at the time, you reasonably assume you have a pretty decent chance to get that TD with very close to 2:00 minutes left and 1 timeout in your back pocket. Your thinking is, if you get the TD you can either:
A) Kickoff deep to GB, putting them at their 25 with about 2 minutes left. GB is most likely to run the ball to run clock and make Dallas use that last time out. If Dallas stuffs the run on first down, GB snaps on 2nd down with about 1:15 left. GB snaps on 3rd down with about 30 seconds left. Dallas calls timeout. Assuming Dallas defense has held GB to 4th down, GB punts to Dallas from inside their 45. Now you have a shot at a long punt return to get you in FG position, or even for a win. But lets say GB is smart and punts it so they are more likely to have a net 40 or so yard gain on a fair catch. That puts Dallas around their 15 or 20 with 30 seconds left, needing to get just 35-to-40 yards to be in position for a FG attempt to tie.
B) Onside kick. If GB recovers (extremely likely), they have it at the Dallas 35, already in their kicker's range. If Dallas stuffs GB on first 3 plays, GB probably gets 3 points for a 6 point lead, but Dallas still gets the ball back with about 30 seconds left, needing a TD. Chances are slim, but it is still a game.
Now let's look at your scenario. Kick the FG as soon as you are in range, which in this case would have been with 2:45 left. You are down 7. Now you can either:
A) Kickoff deep to GB. With 2:45 left it is hard for Dallas defense to stack the box to stuff the run because there's a much better chance GB will still pass. But even if GB does elect to just run the clock and as before Dallas stuffs it, GB snaps on first down and gets it to about 2:40 or so. Dallas calls last time out. GB snaps 2nd down at 2:40 and takes the clock down to the 2-minute warning. Snap on 3rd down takes it down to about 1:15 by the time they punt on 4th. Compared to option A above, you have 45 additional seconds, but must have the TD, so now you have to go 80-85 yards to tie... and it must be a TD. That's an additional 40-45 yards Dallas would have to get with those extra 45 seconds, and with no timeouts. GB is not going to give up a big pass play, and is going to try to make sideline catches much more difficult. They are not going to care if you run it, so will be able to rush 3 if they want and drop into coverage, knowing Dallas has to pass.
B) Onside kick with GB almost assuredly recovering. Again, already inside the Dallas 35. If they don't get a single yard, they have a kicker who set the NFL record for longest field goal. With 1:15 left GB kicks a FG to go back up 10. Game effectively over.
Truly, I don't understand why you are struggling with this. If a coach did what you suggested, I believe they'd be ridiculed for it the rest of their careers.