The real deal y0
No you dont. Lineageos supports a lot of phones that are still supported by their manufactures. Hell my fp4 is still in support too, and lineageos runs fine on it :p
Youre thinking of unofficial lineageos builds and ports to non-supported-by-lineageos phones
The individual members of the foundation most certainly do linux dev, which benefits their specific company. Think kernel or driver adjustments or supporting newer hardware for servers/datacenters.
However, that doesnt mean its only the foundation doing the work, thats just the paid work being done. The rest is all passion projects of people
Not sure why youre getting downvoted, you are right. If you got access to knowledge via your job that has nothing to do with your job and use that knowledge, youre fucked.
For example, you work in a team that makes a ecommerce website, and have access to the wms team’s files. In those files you read about barcodes and their rules/parsing specs, some of those files are only to be read under a contract. Making anything related to the barcodes, even in your own time and equipment, is a nono.
Trust me, ive been in the grey zone and have contacted lawyers about it.