Swakopmund has a bit more options for night life and sightseeing, but you can also easily get there. I can recommend
Daily Shuttle Swakopmund | Shuttle Walvis Bay | Shuttle Windhoek | Shuttle services Namibia as one way to get to Swakopmund if you do not have a car. If you can catch a bus transferring other passengers to Swakopmund, the ride can be as cheap as 50. If they drive you alone it is 200 NAD.
If you a taxi from Walvis Bay to Swakopmund then it will cost between 100 and 250 depending upon your negotiation skills.
Getting a taxi back can be a bit of a pain, particularly after 22:00 in the evening. I managed it always for a price of around 100-150 shared, but it wasn‘t the most comfortable ride. Make sure that your driver is sober!
https://swakopmund-dial-a-cab.business.site Offers 24 hour service that you can pre-arrange. I did not try them, but they seemed to be a upper-scale outfit. I remember there prices being about double regular taxis.
If you will not be drinking alcohol, then a rental car will probably be the nicer bet.
In December and a bit into January there are roadblocks and they are looking for seatbelts, drivers licenses, alcohol consumption, etc.