If somebody needs a 64 bit Linux with newer kernel and UEFI support, I have done a MX-Linux respin in the spirit of SliTaz. Iso size with 1,3 GB is definitly not SliTaz like, but 150 MB RAM is not so far.
I cannot help Filou, shann, alanyih, gibor, sofia-m, because of missing skills, but I am trying since more than a year to find something similar. Its definitly not SliTaz, which is the best, but I find it useable, when you are used to SliTaz for a lot of years.
https://forum.mxlinux.org/viewtopic.php?f=127&t=64016&sid=6d83c0df779959954c2d7376cf59d833
I hope, it can be useful for some users, until next SliTaz is stable.......