brob

Mini-ITX is a less than optimal choice for a system intended to have a long useful life. Right off the bat memory is maxed out. What happens if you need to upgrade to 128GB? Further, small cases have fewer options for upgrading and tend to run warm. The Nzxt H210 is not known for good airflow. The single 120mm top fan is going to have issues dealing with exhaust of two 120mm fans on the cooler. If you do stay with mini-ITX and the ProSiphon Elite consider a case like the Define Nano. It has two 120mm top fan mounts. It also accommodates ATX psu. Like the 12 year warranty Seasonic

Orico makes a number of external enclosures, including one that can be daisy chained. https://www.orico.cc/usmobile/product/detail/id/7164. Startech also has multidrive models, but I believe they are usb 3.0 or eSATA.

The cpu, gpu, and memory pricing doesn't seem right, extremely inexpensive. On the other hand, the psu is significantly more expensive than uk.PCPartPicker.

There is the larger and much more expensive Enthoo Elite. It has space in the bottom for drive bays.

It's tighter than I thought it would be. Can you put anything on the back side?

You would be giving up a lot of general system performance for ~8% better single thread performance.

I'd suggest a higher performance gpu and cpu. PCPartPicker Part List CPU: AMD Ryzen 5 3600 3.6 GHz 6-Core Processor (€203.99 @ Alternate Belgium) CPU Cooler: be quiet! Pure Rock 2 CPU Cooler (€40.95 @ Bytes At Work) Motherboard: Asus PRIME B550M-A Micro ATX AM4 Motherboard (€99.89 @ Alternate Belgium) Memory: Crucial Ballistix 32 GB (2 x 16 GB) DDR4-3600 CL16 Memory (€228.96 @ Azerty) Storage: Western Digital Blue SN550 1 TB M.2-2280 NVME Solid State Drive (€116.95 @ Bytes At Work) Video Card: MSI Radeon RX 6700 XT 12 GB MECH 2X Video Card (€853.99 @ Alter

Not sure what you mean by convert. There are notebook cooling pads which may take care of the cooling issues. I've added a wireless mouse and keyboard to my desk bound notebook and an external monitor. I also added a 1TB ssd.

Yes there are WiFi home security cameras. A large variety in fact.

Why 2 NVMe drives?

For the described use case a 5800X offers better performance. Changed to a motherboard that should be compatible with iCUE so lighting can be sync'd. Wasn't clear to me why a cpu cooler was omitted. Added an iCUE compatible aio. NVMe drive is available for the price of the SATA ssd. Seasonic builds excellent psu. The OneSeasonic Focus GX-750 is well suited to the build. PCPartPicker Part List CPU: AMD Ryzen 7 5800X 3.8 GHz 8-Core Processor ($447.99 @ Amazon) CPU Cooler: Corsair iCUE H100i ELITE CAPELLIX 75 CFM Liquid CPU Coo

The NH-U9S will do a reasonable job at stock settings. If you have not acquired the cpu and motherboard and don't intend to overclock, consider getting an i7-10700 instead.

Some alternatives. PCPartPicker Part List CPU: AMD Ryzen 7 5800X 3.8 GHz 8-Core Processor ($447.99 @ Amazon) CPU Cooler: Noctua NH-U12S chromax.black 55 CFM CPU Cooler ($79.95 @ Amazon) Motherboard: Asus ROG STRIX B550-A GAMING ATX AM4 Motherboard ($177.73 @ Amazon) Memory: Crucial Ballistix 32 GB (2 x 16 GB) DDR4-3600 CL16 Memory ($187.95 @ B&H) Storage: Sabrent Rocket Q4 2 TB M.2-2280 NVME Solid State Drive ($299.98 @ Amazon) Video Card: NVIDIA GeForce RTX 3080 10 GB Founders Edition Video Card ($800.00) Case: Phanteks Eclipse P500A D-RGB ATX Mid

Use hk.pcpartpicker.com instead. It only has one merchant, newegg hong kong, but posting build lists is much easier. You can also enter custom items and pricing.

You shouldn't need the thermal compound. The aio will come with either a pre-applied patch or tube of compound. Build looks fine. You might see if you can get an MSI RTX 3070.