Good writeup! In general, the direction in modern aerospace is to use COTS (commercial off-the-shelf) parts with redundancy and failback for radiation hardening.
If you’re into this sort of thing, I co-write a weekly newsletter about the space industry and often talk about software. https://orbitalindex.com
I'd worry that the COTS approach might be fine for dealing with cosmic rays within the Van Allen belt but it might not be sufficient to deal with the solar wind if you're going to GEO or Mars.
Just FYI but OI has become a great resource for me and my team to maintain situational awareness on what's going on in the industry. Thanks for all you do!
If you’re into this sort of thing, I co-write a weekly newsletter about the space industry and often talk about software. https://orbitalindex.com