The verdict

CPU
Lenovo ThinkCentre M90q has 2.4x the CPU throughput (12,829 vs 5,333 PassMark).
Plex
Beelink EQ13 transcodes more 4K HDR streams (~5 vs ~3).
Networking
Beelink EQ13 has more NICs (2 vs 1) - better for a firewall or VLAN trunk.
RAM ceiling
Lenovo ThinkCentre M90q takes more RAM (64GB vs 16GB).
Local AI
Lenovo ThinkCentre M90q has a PCIe slot for a low-profile GPU - the other needs a DIY build for local LLMs.

Which wins for each job

Job Beelink EQ13 Lenovo ThinkCentre M90q
Plex / Jellyfin ~5 streams win ~3 streams
Frigate NVR ~4 cameras ~4 cameras
Proxmox / VMs 5,333 PassMark 12,829 PassMark win
Firewall / router 2 NICs win 1 NICs
Local AI / LLM no slot PCIe GPU slot win

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 EQ13 Lenovo ThinkCentre M90q
Price (list) $229 $220
CPU Intel Processor N100 Intel Core i7-10700T
Cores / threads 4 8
PassMark 5,333 12,829
iGPU Intel UHD Intel UHD 630
NICs 2 1
NIC model Realtek RTL8111 Intel I219-LM
RAM max (GB) 16 64
M.2 free 1 1
PCIe slot none x8-lp
Idle (W) 11 11
TDP (W) 6 35