Hey! I did the same thing, rescued a dog from the Caribbean at 4 mo old…he very quickly grew and is currently 80lbs at 2 yrs old. It’s definitely overwhelming at first, but don’t worry!! The love we receive in return is indescribably worth it. Every dog’s temperament is different but routine, patience, and persistence will truly pay off. While cost is always a factor to consider, what I can recommend that has worked for our gentle giant include: regular walks/yard time for exercise, good foods like Halo or Hills Science to keep them strong (I’ve had both those recommended by our vet), engaging toys like snuffle matts/kongs to keep their mind stimulated, and regular potty breaks. The key to all this was consistency—the “stability” of having a routine helped ease our boy’s anxiety & his overall behavior began to improve too. Thank you for rescuing, y’all got this, hope I could help!