In fact, the UAW's members appear to have lost this fight. It's difficult to calculate the exact impact on the typical GM employee, but it's possible that many of them will only net a small financial gain from the new deal.
Consider that employees had to go without a paycheck for more than four weeks. The differences in pay that they'll receive in the tentative agreement compared to what they would have gotten without a strike may only be enough to backfill what they've already sacrificed.
The UAW also wanted a plan to restore production at idled plants, specifically in Lordstown, Ohio, and Hamtramck, Michigan. GM idled these plants during its previous contract, declaring the plants "unallocated," meaning the plant would have no product to build, instead of outright closing them in order to avoid having to negotiate their closure with the union. The UAW wanted a plan to reopen these plants. The tentative agreement appears to keep the Hamtramck plant open to build a new electric pickup, but the Lordstown plant will remain closed.
There is always a risk that a new contract will increase the company's costs and put it on a path toward bankruptcy. However, the details of the contract that have emerged so far suggest that this won't be the case. It is too early to declare a winner from the strike, but early indications suggest that workers may have gained little while GM, in turn, sacrificed little.