Hello Feahuttaud64
Another question: do you have in addition international tickets for Paris - Switzerland and Switzerland - Munich? That’s not clear from your question.
Basel - Lucerne - Zermatt - Lauterbrunnen - Munich would have been possible itinerary with less back tracking.
The Berner Oberland Pass plus the Swiss Half Fare Card is certainly a viable option. You would need additional tickets for Zermatt to Lucerne / Lucerne to Lauterbrunnen, and for the trips in Lucerne unless you purchase the Tell Pass.
Have a look at the Berner Oberland Pass. The Berner Oberland Pass would cover the route Lucerne to Lauterbrunnen via Brünig (Lucerne Interlaken Express) or via Langnau i.E. (BLS).
Kind regards,
Roland