From what I've been able to find I don't think you are going to find anything like a list of all Commonwealth women's chess champions.
First thing to check is what kind of organization is the Commonwealth Chess Association (the organisation which currently runs the championships). Looking in the FIDE Directory shows that has its own entry in the list of FIDE Affiliated Organizations and is based in Delhi with board members from India, Canada, Sri Lanka, Australia, South Africa, Scotland and Mauritius. So it has reasonably comprehensive commonwealth coverage.
It doesn't seem to have its own website but does have its own Facebook page. There the latest entry is from May this year about Covid and the previous one is about the 2019 championships. There is no mention of 2020 or 2021 championships so it is reasonable to assume that there weren't any.
Surprisingly the Commonwealth Chess Association's own Facebook page doesn't list the winners for any categories! It's almost as if it's not a serious chess organization. Digging further comes up with this article - Commonwealth Chess C'ship participants scammed by organizers.
This throws some doubt on just how serious (or otherwise) a championship chess tournament this is:
According to the regulations, there is only one official entry per country in each category, but in this case, 700 participants across 16 categories enrolled in the event and interestingly, 644 players were from India.
The open section for commonwealth saw 165 players, out of which only 31 were foreign participants from 7 countries and 134 from India. The top 24 seeds were from India. And there was not a single Grandmaster from any other country.
None of the hoards of players who were attracted to this event could achieve the International Master or Grandmaster Norm since the championship did not meet the criteria of having required number of Foreign titled players.
All those who participated from India received certification that they have represented India in the Commonwealth championship along with an official India T-shirt. Apart from paying a huge entry fee, these participants were forced to buy the India T-shirts from the organisers.
The Junior Categories such as Under-10 Boys and Girls, Under-16 and Under-12 Girls saw only 2 foreign participants out of possible 53 countries which form the Commonwealth association.
I'm not quite sure what point the article is trying to make with "only one official entry per country in each category". According to the official FIDE prospectus for the 2018 event:
Entries: Each Commonwealth country is eligible to field one man, one
woman, One Senior (Above-60), one Junior Girl (Under-20), one Junior
Open (Under-20) player and one open and girl entries each in under-8,
10, 12, 14, 16 and 18 as official entrants. Their boarding and lodging
will be provided free in star hotel on triple sharing basis.
Other entrants will have to pay for the boarding and lodging at $120
(Single) and $ 70 (Double sharing) per day.
Please note that, the entry fee has to be paid by everyone unless qualifying for a free entry under the ‘Entry fee’ section.
So, only one entry per country is entitled to free accommodation, sharing 3 players to a room! However as many paid entries as the venue can accommodate are allowed.
However the point that this event didn't qualify as a norm event because not enough foreign titled players entered is pretty damning. In most countries when a norm event is held the required titled players are offered "conditions" which basically means free flights, accommodation (not sharing 3 to a room) plus extra money on top.
OK, so putting aside the lack of seriousness of the organizers, how can we find out past winners of the various categories of the Commonwealth Chess Association championships?
One obvious place to go is to check the chess-results website to see if Swiss Manager was used for the pairings and the results uploaded. Doing a tournament search on chess-results (enter "COMMONWEALTH CHESS CHAMPIONSHIP" in the first entry titled "Tournament" and click on "Search") shows that this did indeed happen in 2015 through 2019 and also in 2008 and 2010.
Looking through the 15 different championship categories for 2019 we see that there are separate open and girls events for U8, U10, U12, U14, U16, U18 and U20 and finally an open event. There is no separate event for seniors (O50 or O65) nor for women. Presumably because there were not enough entries in these events and so they all played in the open and the winners of these categories was the highest placed qualifier in the open.
This makes it more difficult to spot who the winners were in these categories given that the organizers didn't publish separate lists.
