Side content is most valuable when it solves a current weakness or gives you room to practice a build before a harder main objective.
Identify the bottleneck first
Look for weak survivability, poor damage, limited mobility or missing synergy.
Use side jobs to solve a real weakness
Optional content is useful when it funds, unlocks or tests an upgrade you actually need.
Use lower-pressure encounters to learn the build
Side activities can be a safer place to test new weapons and cyberware.
Return to the main mission once the bottleneck is reduced
Do not let optional content become another endless checklist.