Sleep sack tog rating....

Okay so I’m going to be honest I used a blanket with my first baby 5 years ago. She didn’t move much in her sleep and I really didn’t worry about it.... I’m trying to do better this time around but my gosh sleep sacks are so confusing! I have ordered 3 different ones and they’re just so thin! I’d rather not have a ton of clothing layers on my baby because I just feel like that wouldn’t be very comfortable. I don’t like a ton of layers. So anyways..... how do you determine the TOG? Like I see all different ratings. I live in Texas so it doesn’t get very cold but I like to keep my house like 68° at night. So would a quilted 2.5 TOG sleep sack be right? She 4 months old and I’m kind of ashamed to say that she sleeps with a blanket right now 🤦‍♀️ because I just can’t find the right sleep sack she always wakes up cold when I use them. I sleep with a sheet and a down type comforter so would my baby be fine in footed pjs and a comforter type sleep sack? I mean that’s basically like having a sheet and a comforter right? Help me figure this out! lol