Before getting the answer to the question, ask yourself first: is your map properly timed? Because everything beat snap divisor-related after this will heavily dependent on how well you time the map, while looking at your latest updated map I can see that you still have trouble getting there with offset, thus making the map unsynced.
The concept of beat snap divisor is actually simpler than you think: it's just a tool to divide each measure to certain parts to match the rhythm. Normally songs will be mapped into straight beat, or 1/4. You can look at any TV-sized maps and guaranteed 90% of them are mapped with 1/4, in lower BPM case but it's double BPM aka #/8 signature it'll be in 1/8 instead.
Songs with swing beats will be mainly mapped with 1/3 or 1/6, also depending on the songs. Swing maps are less common because they're generally harder to map with higher difficulty in mind. One example would be
this one when it's mapped using 1/3.
In less common case we'll have irregular rhythm, mainly with 1/5 (1/7 and 1/9 also counts as irregular as well) with the instance of
this map, of if you want something more stable to follow,
this map.
Even father from the spectrum we'll have 1/12 and 1/16 which are way more situational and niche to use, but reaching from this point onwards mean you're already experienced in mapping so I'll not put any more comments here.