Yes if you use a sub your speaker will work less hard no doubt, but only one problem.
The unit (receiver,integrated) must have a X-over or it's going to be a little hard to separate the bass from midrange, tweeter action.
BUT.....But someone just said, I will use the X-over in the sub/subs. I never liked doing just that, more connections, more speaker cable, and if you try to save money you most likely have a inexpensive sub which equals crappy electronics and questionable bass...
Damn it just buy a better amp....lol 🇸🇪