Did you try your sim in another phone that works?

Does the ebay listing mention it works in Canada for Rogers/Telus/Bell?  What is the model number (SM-A526B, SM-A526B/DS, SM-A5260, SM-A526W, SM-A526U, SM-A526U1)?

Until I can get my SIM card working the A52 I have my SIM in my current phone which is a Galaxy Note 9 international version.

The model of the Galaxy A52 5G is the Canadian model https://www.samsung.com/ca/support/model/SM4A526WZKAXAC/

The eBay listing states that the phone is carrier unlocked which although vague heavily suggests any carrier should work with the phone.

When I had my Koodo SIM in the A52 the phone had my phone number in it and even put Koodo’s app on the phone.

If the sim works on on your old Note 9, then it is not a sim or account issue.

If it is indeed the SM-A526W, then it shouldnt be a compatibility issue.

Have you tried a factory reset?

If that still doesnt fix things, the only other possibility is that there is a defect with the phone itself.

I shall try a factory data reset just don’t like to do that unless absolutely no other option.

Nope, I put my SIM card in the phone, and the cycle disappeared and reappeared after a second as it did before, I guess that means there is something wrong with the phone? :|

Have your tried checking if the device is listed as lost or stolen in Canada? As if that’s the case it won’t be able to be hooked up to a Canadian network. https://www.devicecheck.ca/check-status-device-canada/
you can go here and put in the device IMEI (found in settings under about phone) and see if that’s the case. 

Nope, it has not been reported as lost or stolen.

When you put the Koodo sim card into the new phone, Did it ask to “restart and switch to Koodo”? As well do your phone have wifi connection when you reset? 

If you saw the circle with a slash, there might be issue with firmware that wasn't compatible with Koodo.

At first, yes the A52 did request a restart which I did do, after that I still got the circle with a slash but the About tab clearly tells me my phone number AND the Koodo app pops up in the app drawer which I assume has been defunct since it just opens a web browser window. Also, the A52 does have WIFI connectivity just not cellular.

Based on this reddit thread some people say it’s firmware and some say it’s hardware.

https://www.reddit.com/r/samsunggalaxy/comments/17py6s8/galaxy_a52_no_service_after_update/

I would try to update your phone to its latest firmware first then reset the phone to its default factory settings with the Koodo sim card in it to see if that can help. If not, you might have to return the device

It is at the latest firmware. Any way, I just spent the last hour messing around with zip files seeing if I could get a modem that works properly and I bricked the phone once by flashing a modem that is apparently too old and doesn’t have a bit value that Samsung approves of, so then I reflashed the entire operating system to get the phone to be operable again but still no cellular service. I don’t know if the seller will take it back because I already opened the phone to fix the back which was broken and replaced it with a new back.

Sideloading firmware isn’t the correct way to update your phone. It can void  warranty as well. I wouldn’t suggest you do it.

I suspect the correct way you’re talking about is opening settings and going to the update tab but another way to do it which is more technical is by downloading official firmware and using odin to flash that official firmware.

As for the warranty the A52 is old, I doubt it has a warranty still.

Any way, any more ideas? I’m out of them short of replacing the antenna.

Yes, the update via original firmware should be the one. Otherwise, it is very hard to troubleshoot. Once you decide to sideload, you are mostly on your own to fix the problem.

It's a used phone with the back already broken.

Replacing the antenna is not even a guarantee to fix the device.

At this point everything is the next best guess and we are approaching the murky point where it's could be anything 

Yeah I must say I am very disappointed and other than returning the device is which problematic on its own I’m not sure what next to do. It’s problematic because I decided to take the original broken back off the phone and replace it with a fixed back BEFORE I tried the SIM card to see if cell service is working properly. Apparently I might need to test all radios on future phones I get ahold of.