Check out Heritage Tile Subway Ceramics. They have radius trim pieces.

I’ve used Heritage Tile. They have so many trim pieces that I had never even seen before. Here’s a link to their catalogs.

https://heritagetile.com/subway-ceramics-design-tools/

I also used Heritage Tile for my bathroom (check out my profile) I am local to them in Chicago but they were great to work with. You may have sticker shock - I tried to keep the number of transition pieces to a minimum - we only did one corner using the round outside corner feature. The inside corners were just cut and butt. If you do use them, they are very high quality tiles and they cut and install nicely. Just make sure your walls are plumb and level as much as possible, because there's not a lot of fudge factor.

The picture you posted is not ceramic tile. I believe it is structural clay tile: laid up like concrete block except that it is made with clay like brick and glazed. Hence the ability to achieve the very rounded corners. Was very big in schools and hospitals at one time.