Three days or five: choosing a split that fits your week
Start with the days you can reliably use, then organise the work.
A split is a schedule
Full-body, upper/lower and push/pull/legs describe ways of organising exercises. Their names do not guarantee results. Before choosing one, look at an ordinary week, including travel, work and recovery time.
Count realistic opportunities
Three available days and five available days create different scheduling problems. A routine that repeatedly loses its final session may leave some planned work unfinished. Compare what you actually attend with what your calendar says you intend to do.
Use examples as organisation, not prescriptions
A full-body schedule distributes different regions across sessions. An upper/lower schedule separates them into two broad groups. Push/pull/legs uses another grouping. These descriptions do not specify the right exercises, loads or weekly amount for you.
Allow for a changed day
An extra workout does not have to replace the whole weekly plan. In JJ FIT, distinguish a workout for today from a saved repeating plan. Multiple sessions on the same date should not be confused with multiple training days when reading the weekly count.
Review the pattern
Look for a plan you can maintain before adding days to make the schedule look more advanced. General activity guidance offers context, but individual goals and health can require a different plan. Keep the record of completed work separate from the plan.