I have been looking for a wide tire gravel frame as well. (Something like a Salsa Cutthroat.) This appears to be a very niche market. I have found a few forks that fit 60mm tires, but gravel geometry frames are no where to be found on Aliexpress.
I believe the reason is that as soon as you try to fit wide rear tires, the frame rear triangle has to become longer to accommodate the tire, or you have to go with a wider bottom bracket. As soon as you start messing with these frame features/geometry, you quickly get into 29er hardtail frame geometries. Therefore just purchase a 29er hardtail frame and repurpose the bike to gravel by putting on more gravel specific parts.