The first method is through Light and Sun.
Any light source can charge your remote.
Position it so the solar panel receives light.
Direct sunlight is best for faster charging, but standard indoor lamps are also suitable.
Unfortunately, this method of charging can be quite slow.
Samsung mentions it takes about 2 hours but often takes longer (around 4 hours).
Use a USB-C cable for a quicker charge or when theres no light available.
Samsung TVs have a special indicator showing the remotes battery charge.