Open Smite on your Xbox and make sure you are signed in to the correct Xbox account
Go to the official Hi-Rez account linking page
Sign in with your Hi-Rez account or create one if needed
Select Xbox as a linked platform and connect your Xbox account
Sign in with your Steam account on the same Hi-Rez linking page
Select Steam as a linked platform and connect your Steam account
Confirm both accounts are linked under your Hi-Rez profile
Launch Smite on Steam and sign in with the same Hi-Rez account
Make sure cross-progression is available for your accounts and region
If items or progress do not appear, restart the game and recheck the linked accounts