IOS: is it possible to side load the built code

Tot test the app on a real iPhone rather than in the simulator?
Thanks,
Dick

You have to build rather than run but you should be able to load it
Connect your device to your PC.
Open Xcode, go to Window ? Devices .
Then, the Devices screen will appear. Choose the device you want to install the app on.
Drag and drop your . ipa file into the Installed Apps area

According to apple any device you “side load” will run for ONE YEAR before you have to “load it again”.
This is not a Xojo restriction, but an Apple one… I have run across this a few times with apps I wrote for myself using Swift

Yes, but you’ll need proper Apple certificates and profiles.

More information here:
https://documentation.xojo.com/topics/application_deployment/mobile/device_deployment.html

I understand that the easiest is to also submit the, in the simulator working, test versions to Apple?

not sure in Xojo, but in Xcode, you simply select your connected iOS device (assuming you have the above mentioned creds)

Do you meant a paying developer account ?

yes he does