It should work, I spun up a Debian 12 LXC and installed IncrediblePBX 2025 (for the newer FreePBX and Asterisk) and it runs flawlessly. FSPBX or FusionPBX on the other hand, not so much... I haven't been able to get Freeswitch to start as it hits permission errors trying to do CPUScheduling Policy. I can turn it off in the systemd file, but the installation script just turns it back on.