Guide on properly creating and maintaining a home server

Hello! First time posting here.

After finally internalizing all the recent videos posted on the channel in regards to having a home server, bit rot, and data recovery, could you please make a guide or tutorial on data stewardship.

Current newbie setup:
3 drives in use on windows, 2 of them used for plex media server.
3 drives are stored as backup storage (in antistatic packaging)

1 external drive in use for nextcloud (photos)
1 external drive stored as backup storage

Questions and concerns:
How to deal with bit rot?
Which os or file system is best to use?
Best way to store media?
EEC memory needed?
Do cold backup drives need to be spun up once a year or need some other maintenance?
How to best physically store hard drives?
Didn’t zfs not help Linus from LTT with his data?
How to best check data and how often should it be checked?
How to best copy and paste data?
If any errors or problems, how to best recover data? (Should the data just be deleted and copied from backup?)
When is raid helpful? Real time checking or repair? Is it better for plex?

These are all the questions I currently have with my limited tech knowledge. I don’t know much, but I need the basics in order to swim.

Thank you for reading and I appreciate any response!