You’ll usually end up paying more in the long run then if you went with unlocked and a MVNO.

You're missing a component: you can buy used phones and go with an MVNO and skip the contract subsidy requirement for savings

I purchased a used carrier locked flagship phone for $250 when they were still selling for $1100 as new carrier-unlocked, then put it on my MVNO which is a subsidiary of the primary carrier (so the carrier lock doesn't matter).

You can't get those cost savings with a new contract phone nor a new carrier unlocked phone.