I’d be very surprised if the Mint team keeps the regular mint releases going instead of just going all in on LMDE
From what I’ve seen they like to take things slow. However I agree that it’s only a matter of time now. Ubuntu also plans to have the next distro LTS released as both a regular iso and a snap-only read-only version.
In other words two iso’s will be supplied and one will be immutable and every component and library will be all snaps only. This is the future they envision for Ubuntu so Mint will definitely have to move to Debian only eventually.
I’ve used plain old Debian since ~2016 and only just tried LMDE this month, it’s really nice! I prefer Gnome but the default LMDE desktop was perfectly usable and clear, and I really like that it walks the user through setting up automatic backups. I would definitely recommend it over Ubuntu now for new users.
For whatever reason, when i tried to fresh install lmde 6 two weeks ago, it absolutely refused to set up grub properly for me. Something in the installation just refused to work, despite reformatting and setting up partitions in both the automatic and manual configurations. Hopefully other new users have a smoother time than i did?