"Out of pocket"....
Startup? Business Plan?
Is there a budget?
That rack mount NAS does not come with disks. (Reference Customer Q & A #3.) Also no rails.
And you need rack(s), power, cooling, etc..
Not questioning RAID 6 per se but is RAID 6 truly a requirement for the AI project? Or someone has just decided to use RAID 6 versus some specific reason or requirement for doing so. Data can still be lost.
Not a RAID person (full disclosure) so I cannot really question the details.
However there are trade-offs involved.
For example:
https://techgenix.com/raid-5-vs-raid-6/
I believe that I have a sense of what you (Mechanical Engineer)/your role is: and that role is to basically to build/provide the rack(s) to hold everything. Correct?
You should not be concerned about what RAID for example. The OS, the AI software, - not you. Disk drives and drive capacity - not you. Network requirements and performance - not you.
Accommodating the required number of disk drives, power requirements to the rack, motherboard, drives, and proper cooling, etc. - mostly you I think.
Remember access, maintenance, and physical security. All very important.
= = = =
Unfortunately this is one of those situations where a "group of friends" can quickly end up as no longer friends.
Especially as the initial startup investment and required operational expenses start to grow.
Define/quantify marginal gains... Actually for many startups immediate gains are rarely expected. Planning includes allowances for initial losses.
My recommendation is a serious, mandatory "all hands on deck" group meeting to identify the specific objectives, requirements, and assignments.
You need to design to specific written requirements that are provided to you.
If you can design and build to those requirements - then good. If not, then you provide the necessary feedback as to why not and perhaps offer options within your purview.
Just my thoughts on the matter.