A shame. I'd kind of become a fan of the Taka look and was rooting for Mirage. Ceroptesian is hardly bad, though. I just found it a smidge on the blander scale than Mirage, though I liked it better than Painting, which looked more like something from Ubuntu,
I did make a submission (Cathode), but I freely admit it's not great.
Old isn't necessarily bad. Also, as far as I can tell, distros are still patching 1.32. Based on my personal usage of LightDM and the fact that the project is still developed (based on commits to main), I'd say it's more of an "if it ain't broke, don't fix it" dynamic. As for security, the active development suggests the developers would respond if there was a vulnerability - a big if, considering its last CVE was in 2017.
Personally, I love LightDM - it has just enough features while mostly sticking to its name (I mean, you're probably using GTK anyway).