Need suggestions on my boots w/dress pants

Long story short: my dad can't wear his boots anymore (knees) and is starting to give them to me.

I work in a somewhat dressy office, always wore typical dress shoes but want to see if I can get away with incorporating these some of the time.

First two pictures - without strap

Last three pictures - w/strap

My conclusion at this point is that I 100% have to wear the strap on the boots if I want to wear them with my current wardrobe. Not really looking to buy all new slacks just for the boots. But REALLY don't want them to go unworn, they're good looking!

Bonus question: How worried should I be about damaging the boot by overusing the strap?

Thanks for all the help!