I am happy to drink sparkling Larger, a 500 ml swing top primed with 1/2 teaspoon of granulated sugar, but when I brew Stout or Ale I prefer a less fizzy "draught" brew.
Not understanding the chemistry happening during the priming-conditioning stage
To a first approximation - the chemistry is that bubbles are proportional to sugar, so halve the sugar and you halve the bubbles.
In fact it's a bit more complicated than that, as up to half the final carbonation comes from CO2 left dissolved in the beer from the main fermentation. The solubility of CO2 varies with temperature, so a lager might end fermentation with 1.3 volumes of CO2 but a kveik fermentation might end up with just 0.7 vol. Carbonation is expressed in "volumes of CO2" relative to the volume of liquid, so 1 litre of CO2 in 1 litre of beer is "1 volume", 2 litres of CO2 in 1 litre of beer is "2 volumes", or 2vol for short and so on.
So if you've fermented an ale at 20°C and not sloshed it around too much or left it too long after fermentation, you might be starting at 0.8vol. Then adding the following grams of white table sugar per litre will get you the following carbonation :
1g/l -> 1.1vol
2g/l -> 1.3vol
3g/l -> 1.6vol
4g/l -> 1.8vol
5g/l -> 2.1vol
6g/l -> 2.3vol
Different sugars have different fermentabilities so will need more or less - you need about 50% more DME or honey than white sugar. As per above, you might have 0.5vol more CO2 already in the beer from a lager fermentation (if you bottle at lager-fermentation temperatures, it's the maximum temperature before bottling that matters), and a bit less from a kveik fermentation.
Cask beer in the real world can be as low as 1 vol once it's been tapped a while, but personally I like around 1.7-1.8 vol for British beers. I add a bit more sugar to 330ml bottles than 500ml bottles as the extra headspace:volume sucks up a bit of carbonation. Lagers are typically around 2.5vol, wheat beers and some Belgians can be 3.5vol or more (and need special strong bottles to cope - bottle bombs are a bad idea).
See priming calculators like this one if you're eg using different sugars :
https://www.brewersfriend.com/beer-priming-calculator/