S5II Beginner: Is it worth adding the 18mm f/1.8 to my kit (20-60mm f/3.5-5.6) for my roadtrip and for storytelling videos?

Hey everyone,

I’m a beginner to outdoor photography and video. I understand the basic terms and exposure concepts, but I consider myself pretty new when it comes to actual field work. I'm prepping for a 2 month road trip and trying to finalize my camera kit.

Current Kit:

1) Lumix S5II with the standard 20-60mm f/3.5-5.6 kit lens,

2) DJI Action 4 (for vlogging and action/quick scenes)

3) NiSi Swift True Color Variable ND Filter (1-5 Stops, 67mm for daylight)

What I'm Shooting:

\- Setting up camp and building campfires at night

\- Walking various landscapes in nature in different weathers

\- Sunsets, early sunrises, and dusk scenes

\- Backpacking forest, mountain, deserts, and in fields

\-Splashing into basic astrophotography / night skies MAYBE

My Dilemma:

I'm debating whether it's worth the money to add the Lumix 18mm f/1.8 to my setup alongside the 20-60mm (not replacing it, just adding a prime). I'm mainly worried about low-light situations at night around camp. I know the 18mm f/1.8 can handle much lower light levels than the 20-60mm at f/3.5, but as a beginner, would the 20-60mm be "good enough" for night camp setups, or will I heavily regret not having the extra light gathering of the f/1.8?

Also, for basic astro, can the 20-60mm at f/3.5 get the job done, or is the 18mm f/1.8 pretty much a necessity to get decent star photos without massive noise?

Is it worth saving the cash and keeping things simple and light with just the 20-60mm + Action 4, or should I go for it and add the 18mm f/1.8 to the bag? Appreciate any advice from those who shoot outdoors!