When you actually need jungle boots for balls out, mud to your ankles and knee deep water there are no substitutes for the old Wellco Boots.
I have a pair of the original OD ones in like new condition. Got them from US on Ebay for $35 plus shipping US. I wear them only once in a blue moon. They aren't the most comfortable walking on anything other than wet, muddy swampy terrain in hot weather. But I haven't seen anything that can outperform them in those conditions.
Most modern "jungle boots" are just regular boots with thin lining and drain holes. They aren't true dedicated jungle boots.
OP, Ebay is your friend. I found my brand new with tags pair on there. I'm a 9R in the Wellco military issue ones. There's no half size in the old school ones. The all black later variants do have half sizes. Good luck in Canada. Buying anything in this country is a nightmare. Terrible websites and zero selection.
I have had a few pairs over the years and will say that my brannock foot measurement is 9 1/2 Medium and I wear a size 9R in the old school boots. So usually a half size down from your brannock device true foot size SHOULD fit you. That will get you started if you're looking online/ebay. Also beware that a lot of the brand new ones still around are still around because they are factory rejects that are badly stitched inside the boot and you may find them excessively tight over the top of your foot to the point of pain. Hence why noone has actually worn them and used them.
Ask yourself if you really need true jungle boots though. The old Wellco's are almost only good for that terrain. If you're going to be wearing them anywhere else, you're probably not going to find them very comfortable as the mesh insoles don't cushion the impact of your steps etc The stiff steel shank in the sole does not aid in this either lol You may find them very hard on your feet and hence knees and back in anything but soaking wet, soft ground/mud. Then if you add a cushioned insole to them, they may not fit properly anymore.
The only other option I have found decent is the Rocky S2V Jungle variant. However you will need to replace the stock sole as it is in no way designed to be used in true hot wet weather conditions. It sucks up moisture and traps it rotting your feet. You can swap it for a wet weather aftermarket sole. Other than that they are damn near equal to the old school versions for venting water and fast drying/light weight. However again, the rocky soles don't have anything on the old panama soles. The heels don't shed mud as easy and you will never find better traction in wet mud than the panama sole.
Hope that helps!