iPhone 17 Constantly Dropping Calls

Did anything change around the time it started, an iOS update, a move, a new area? As well, is it dropping everywhere or only in certain spots, indoor or outdoor, and do others nearby on Koodo or Telus have the same problem in the same places?

You didn't mention reset network settings or reseating the SIM, so I would do those two first. Power the phone off before removing and reinserting the SIM. More tips here https://www.koodomobile.com/en/help/im-not-getting-any-network-service

If nothing changes, put your SIM in another phone. If the problem follows the SIM it points to the SIM or the account, if it stays with the iPhone it's the device or the coverage in your area.

Have you asked your friends and neighbours using Telus or Bell in your local area to see if they are experiencing the same issue? Do you get a better signal once you leave the area?

What area are you in? 

When you calls drop is your Signal low? 

I believe I had an iOS system update recently so right now I’m on iOS 26.6.1. It happens typically when I’m in my house indoors (that’s when I usually call) - but it never had a problem until now. No specific spots in the house, but that’s usually the only time I call. My friend also has Koodo but neither of us can tell which of us is dropping (I suspect it’s me). How do I reseat an eSim? I’ll try resetting the network settings.

Signal is 3 bars or less, sometimes my calls have dropped when I had full bars. 

I looked at downdetector and nothing major seems to be happening. I’m from Edmonton Alberta

An eSIM can't be reseated physically, but the equivalent is Settings > Cellular > tap your Koodo line > Turn Off This Line, wait about 30 seconds, then turn it back on. While you're in there, go to General > About and leave the page open a few seconds — if a carrier settings update is pending it'll prompt you there.

One thing I would recommend you do : turn Wi-Fi calling back ON. I know you turned it off as a troubleshooting step, but the drops are happening indoors at home on 3 bars, which is exactly what it's for — it hands the call to your home Wi-Fi instead of a weak cell signal. Leave it on and only turn it off again if the drops continue, so you can compare.

Then do the network settings reset (it clears saved Wi-Fi passwords, and you may need to re-enable Wi-Fi calling after it comes back).
 

I'm in Edmonton as well. 

Do you have calls drop when you are outside?