OMV + SnapRAID + MergerFS

Hi guys, I'm a complete beginner at this whole Plex/server thing.

A few weeks ago, I set up an old laptop win11 to run Plex and have fallen in love with it. Unfortunately that little drive is getting full, so I'm looking to whip up something else with some long term potential.

The plan is to build a server for my family and host not only movies and TV shows, but songs, family photos, and family videos.

I'm planning to Frankenstein some old parts sitting around into a small server: - gigabyte H310-M - 16GB ram - Intel i5 8400 - a random mix of HDDs (500GB + 1TB + 500GB + 350GB)

My mobo only supports 4x SATA drives, so I'll be getting a PCIe to SATA card to expand that.

The main limiting factor currently is my cash flow. It'll be quite low for the next 6-8 months, so I'd rather not spend any money on this if I can help it.

After that, I plan to slowly purchase larger drives and add them in to the server, and once I have ~10x drives, to slowly replace the old ones. I might have to start off with second hand drives which might not be the most reliable.

My main considerations are to protect the system against at least 1x drive failure, and to allow for me to replace a HDD to expand storage without too much trouble (i.e, remove smallest drive, replace with a bigger drive, rebalance data)

The family photos + videos I'll backup externally outside the server intermittently as they're too valuable.

Some research has me thinking openmediavault + SnapRAID + MergerFS might be the best free options around for my needs

I found this dude's YouTube step by step guide that seems super helpful: https://youtu.be/wHMrptwNz2I

Does anyone have any recommendations in setting this up? Do I seem to have the right idea?