well, the cash up front counts against the over all contract equally devided in the years and with the salary for the year counting against the cap. one of the tricks is for owners, to add years to contract, and payout cash up front, which is of interest to players and it lowers cap hits, and pushed dead money to future. not all owners all willing to put cash out.
so to your point, Dak's current cap hit in 24 is 59, dead cap money is 61 M, his salary is 29 M. so 30M is from previous restructures and bonuses paid out. they can restructure again, perhaps add a year, and push some of 29M to future and spread that 30M into future years. doesn't necessarily mean he is getting a new contract, its spreading the money in additional years and maybe reduce the 29M salary to 10M and give him 19M up front and spread that into future years and depending on number of years added, the cap hit of 59M becomes 30M or something (don't get hung up on the actual numbers, my point was the ...creative salary cap accounting that happens in NFL).