How can I housetrain my Shi-Chon?

Hello I have a Shi-Chon (Half ****-zu Half Bichon) and she is going on 2 years old this October. She was spayed after 7 months of having her.

My issue is that she doesn't seem to mind whether she urinates and defecates inside the house or outside the house...

I feed her once in the morning and have started to only give her water in the morning as well which I'm sure is not recommended.

I feed her in the morning and then take her out immediately afterwards, and she does both outside just fine. I was leaving her in the upstairs of my house with access to her bed which is in my bedroom and the hallway. It's all hardwood floors. I would then usually come home at noon from work to let her out again, but half of the time she would have urinated on the hardwood while I was away.

I tried potty pads and I would come home to find she chewed those to bits, then I crated her with a potty pad and that was torn to bits inside the crate. Even put the stuff from Petsmart on the pads to try and get her to go on the pads.

So now I crate her during the day and I had to put a cardbox box in the crate with her to limit her space. This works great even though I feel bad leaving her in there during the day with such limited space.

So I then I would come home and take her out and let her go and again she would go outside just fine. But if I let her come and drink more water, in 1 or 2 hours I would walk in the hallway and she had urinated again. She doesn't let me know by barking or whimpering or walking circles, she just seems to think it's okay to squat and pee on the floor whenever she needs to go.

She will also defecate right on the floor as well in the same fashion but this is only limited because I only feed her in the morning.

Now I'm just in the habit of buying hardwood floor pet cleaner with no expectation that this problem is going to go away. I've tried taking her out more often which works, but the main problem is if she's inside and need arises she has no qualms about going inside.

A couple times now I've had to use peroxide on my floor to lighten a urine stain that sat too long and then re-stain and clear coat that area.

She's a very nice little dog other than this and loves everyone she meets, it's just this housetraining is not going well at all and at 2 years I'm really at a loss of what to do about it.

Thanks for any advice!

Matt