Most common cause for a foundation to bow or crack like this is when the foundation wall is not being shored-up during backfill and when too much dirt is pushed against it during backfill, that will usually cause the wall to bow and crack, seen that happen many times.

Surface repairs with mortar that is a temporary solution to close up the cracks and the crack could open up again if there is foundation movement so you have to keep an eye and see if the crack will open up and if it does a much better repair solution should be used.

Steel you have there now is an approved method by most engineers because we always get this repair details for such repairs. By the way, did they use Channel Steel or this is low profile I-Beams?

I do a lot of foundation repairs but I use Carbon Fiber Straps or epoxy injection with use of Staples and we been successfully changing steel to straps instead and been using them for the last 10 years give or take,

The reason using Carbon Fiber straps instead of steel is more effective is because straps are much stronger and better at stabilizing the foundation and preventing further movement in comparison to steel. Straps have an elongation of 1.5% and steel has an elongation of 6% so under pressure the wall will move 6% before steel will react, not to mention straps are only 1/8" thick and can be slipped behind piping, etc without the need disconnecting anything or re-routing.

If you really have concerns you should have a structural engineer to come out and inspect everything, it will cost you a few hundred dollars but he will evaluate everything and you will know exactly what you have there and if this method will work or not in the long run.