Since @Devil introduced the new solver in May (
https://linuxnews.de/apt-2-9-3-fuehrt-neuen-solver-ein/), I have tested the option and now use it every day.
Of course, Solver 3.0 is still under development, but we also use Siduction, which is based on Debian/unstable. Of course, we also have to keep an eye on the output of Solver 3.0 - the final decision remains in our hands.
In the beginning I was sceptical and compared the solutions of Solver 3.0 with
apt full-upgrade and
apt upgrade.
In the meantime, I only use the new Solver. In contrast to apt full-upgrade, it no longer suggests deleting essential packages or self-installed applications until the problem is solved.
edlin