The verdict

CPU
Dell OptiPlex 7000 Micro has 3x the CPU throughput (16,359 vs 5,386 PassMark).
Idle power
Beelink ME mini idles lower (7W vs 10W) - cheaper to run 24/7.
Networking
Beelink ME mini has more NICs (2 vs 1) - better for a firewall or VLAN trunk.
RAM ceiling
Dell OptiPlex 7000 Micro takes more RAM (64GB vs 12GB).

Which wins for each job

Job Beelink ME mini Dell OptiPlex 7000 Micro
Plex / Jellyfin ~5 streams ~5 streams
Frigate NVR ~4 cameras ~4 cameras
Proxmox / VMs 5,386 PassMark 16,359 PassMark win
Firewall / router 2 NICs win 1 NICs
Local AI / LLM no slot no slot

Approximate - capacity estimates from curated specs, the same logic as the recommender. Verify against your exact setup. Prices move; check the retailer.

Full specs

Spec Beelink ME mini Dell OptiPlex 7000 Micro
Price (list) $329 $330
CPU Intel N150 Intel Core i5-12500T
Cores / threads 4 6
PassMark 5,386 16,359
iGPU Intel UHD Graphics (24 EU) Intel UHD 770
NICs 2 1
NIC model Intel I226-V Intel I219-LM
RAM max (GB) 12 64
M.2 free 6 0
PCIe slot none none
Idle (W) 7 10
TDP (W) 6 35