No, nor is its best case carbon neutral. See my sibling comment about that. It's also worth mentioning here that the typical grass-fed production is actually higher in methane emissions due to longer raising times

Taken together, an exclusively grass-fed beef cattle herd would raise the United States’ total methane emissions by approximately 8%.

https://iopscience.iop.org/article/10.1088/1748-9326/aad401/pdf

Currently, 'grass-finished' beef accounts for less than 1% of the current US supply

https://iopscience.iop.org/article/10.1088/1748-9326/aad401

Or if we look at Australia, which likes to tout its grass-fed production, it's still majority feedlot

51% of domestically consumed beef comes from feedlots. [...] In Q1 2021, 19% of cattle on feed were on feed for less than 100 days

And trend-wise, grain-fed rather than grass-fed is increasing

Going forward, these trends indicate that the Australian grainfed sector will continue to make up a growing percentage of cattle slaughter and beef production

https://www.mla.com.au/prices-markets/market-news/2021/grainfed-cattle-make-up-50-of-beef-production/