KDE: kcursorgen and SVG cursors
Quoting: kcursorgen and SVG cursors - KDE Blogs —
In the latest Plasma 6.3 Beta, you will find a new executable named kcursorgen in /usr/bin. It can convert an SVG cursor theme to the XCursor format, in any sizes you like. Although this tool is intended for internal use in future Plasma versions, there are a few tricks you can play now with it and an SVG cursor theme.
(Unfortunately, the only theme with the support that I know, besides Breeze, is Catppuccin. I have this little script that might help you convert more cursor themes.)