To improve lighting, I usually replace the stock bulbs with either Osram Night Breakers or Phillips Extreme uprated bulbs and that makes a noticable difference. I do this with just about every vehicle (van or car) as a matter of course as good lighting is very important.
On the majority of vehicles (especially older ones), these are a simple DIY swap.
Another cause for poor lighting is low voltage at the bulb due to poor wiring, either degraded over time or from new. You could check you are getting a decent voltage at the bulb (compare it to the
battery voltage when the engine is running) and if low, it is not too tricky a job to upgrade the loom to get the voltage back at a good level. This can make a noticable difference if you are suffering this issue.
Changing the actual headlight fitting on most vehicles is not practical. Some vehicles do have different options depending on the model. For example on the VW T5, there was a standard headlight that used a basic H4 twin filament bulb (a old but common realitively low performance bulb) but the Caravelle models used as standard a twin headlight projector style headlight fitting and it is possible to swap lights to improve. I replaced the physical headlights on my T5 with Caravelle ones and fitted uprated Bulbs, as well as modifying the wiring so I had 4 bulbs on when on Main Beam instead of the standard 2 and that made a tremendous difference.
There are some aftermarket headlights around for some vehicle that are made to just look good but work very poorly - clearly ones to avoid (the VW T4 scene is plagued with fancy but rubbish aftermarket headlights)
Headlight swapping is probably not an option on the Mercedes, but you could fit auxilary lighting maybe? the Traditional "rally style" spotlights would likely suit a vehicle of that era very nicely. Or you could think about an LED lightbar for a more modern solution.