That’s awesome to hear! It doesn’t have to pre-pend with “99-”, but I use “99” to sort of mark the custom files I created manually, rather than those that are included in a distro/package (e.g, “10-”, “20-”, “40-”).
I also employ this little trick to be able to migrate or review my custom system-wide configs.
Perhaps changes in driver development, and a combination of GPU, monitor, kernel, etc? I tend to have the best results with it on Intel graphics.