A global phone has at least 1 or 2 bands for the most common systems used in the world IE LTE/4g and now 5g from what I can tell, many Chinese companies sell phones that include bands for Canadian and most of the world but there are some bands missing like band 50-100 but from what I can tell there not used much if at all.
my wifes phone supports
5G:
NR: N1 / 2 / 3 / 5 / 7 / 8 / 20 / 25 / 28 / 38 / 40 / 41 / 66 / 77 / 78 / 79
4G:
LTE-FDD: B1 / 2 / 3 / 4 / 5 / 7 / 8 / 12 / 13 / 17 / 18 / 19 / 20 / 25 / 26 / 28 / 66
LTE-TDD: B34 / 38 / 39 / 40 / 41
3G:
WCDMA: B1 / 2 / 4 / 5 / 6 / 8 / 19
CDMA EVDO: BC0 / BC1
2G:
GSM: B2 / B3 / B5 / B8
here is the list for my 4g/LTE-only phone
4G:
LTE-FDD: B1 / 2 / 3 / 4 / 5 / 7 / 8 / 12 / 13 / 17 / 18 / 19 / 20 / 25 / 26 / 28A / 28B / B66
LTE-TDD: B34 / 38 / 39 / 40 / 41
3G:
WCDMA: B1 / 2 / 4 / 5 / 6 / 8 / 19
CDMA EVDO: BC0 / BC1
2G:
GSM: B2 / B3 / B5 / B8
after comparing it to the wiki list of all phones bands used there are very few that aren't able to be used, So I don't know but I have always taken the global/worldwide phone as it will work in every major market and even most smaller ones, I could be wrong but I have had a very hard time finding a band that isn't in the list for our phones. the only thing I don't know is if you can use an FDD on a TDD network cause one has a band for up and down, well the other uses one band for both with a time separation.
en.wikipedia.org
en.wikipedia.org
en.wikipedia.org
en.wikipedia.org
but I am not a big phone person, so I could be wrong