It's useless because it's based on IRE measure (old analog one) which has nothing to do with current digital world and gamut measurement which is used today. BM still keeps this about useless option which only misleads people.
Saying this you should not really have problems when exporting from Resolve as it operates in RGB, so this should never produce bad YUV output (if you use uncompressed output).
Any compression will create overshoots- even ProRes etc. and those will create problems, but only if you measure against perfect 100% signal. R103 standard, which is used by most (if not all) broadcasters has threshold which allow for small (or relatively not that small) deviation from ideal signal and any intermediate codec's overshoots should easily fall into this thresholds.
What codec are you exporting to?
How do you measure gamut? Is it against R103 standard?
Don't try to hit 100% perfect signal as it's basically impossible to do with compressed format (and without raising blacks and lowering whites).
Soft clipping (+ luck) slightly above perfect levels is the only option. This is what legalisers do as well- they soft clip slightly above perfect levels in order to give space for codecs to overshoot. This is all based on pure luck as no one can really tell how given codec will "damage" your signal. Heavier compression= more possible problems.
Here is EBU R103 standard. You have 5% allowed deviation at bottom and top+ overall area with those overshoots can account for max 1% of the frame.
Here is also very good summary about current reality:
"The EBU, considering that,
• video levels have traditionally been measured with devices that display a trace, such as a traditional waveform monitor,
•
that readings in mV no longer give relevant information in digital signal infrastructures,• television systems now include high dynamic range and wide colour space images as well as
standard dynamic range and colour space images in the same digital container,
•
that a certain tolerance can be allowed in digital signal levels"

If you take your master and put through legaliser which will "fix your video" it all sounds good, but moment later this is encoded to some format and introduces overshoots again. As I already said- only way is to legalise stricter than ideal levels and pray that codec won't introduce overshoots which even so will go outside thresholds. If a place tries to measure against 100% perfect signal without any thresholds then good luck with it. Ask them to create such a file

Stay away from ticking 'super black/white' in export option as this is a special case for YUV codecs and you rather want to avoid it in general and
specially for broadcast delivery. Make sure all looks good in scopes and it's clearly within 0-1023 levels. Places which cause problems are high contrast areas, specially any borders between dark/bright pixels.
Eyehegith use to have PDF about it. It was part of their BrodcastSafe plugins, but they don't sold them anymore. They had extra "stricter" preset to compensate for possible later compression overshoots.