oh I checked the sourceforge page and in there last update was 2017the newest version i see on lxle's downloads page: https://www.lxle.net/download/
is LXLE Focal 64Bit which is based on ubuntu 20.04 (codenamed Focal Fossa) so it should be supported until 2025. distrowatch and the lxle forum say it was released in may of last year.
obviously you should use a distro you can install so this isn't a post to pressure you in any way, but that 2015 date isn't accurate.
i believe lmde 5 only comes with cinnamon, but you could install xfce: https://forums.linuxmint.com/viewtopic.php?t=375685
totally understood. as a new user, i would have done the same. unfortunately in that situation, you have to do a little digging to figure out how exactly to start the os instead of using just one command.