@luin31 If your BMR is 1400 you are likely not eating enough if you are working out and feel burnt out.
For building muscle perhaps up your portion intake to 1g per pound as a start to ensure you are getting the recovery and building you need.
You likely can increase your caloric intake but hard to know without the data. Do you track your daily burn with a device (ex: apple watch)? That will give you more accuracy on your deficit (although not perfect it’s better than guessing). You might not be eating enough and your body/metabolism is plateauing.
Are you eating carbs before and after your workouts? This will help with keeping your energy up.
Are you following a specific macro ratio? Sometimes this needs to be adjusted by body type if the average recommended for recomping isn’t working for you personally.
If you are feeling 3 days working out isn’t enough - on your rest days perhaps try walking for at least an hour and for recovery days - a zone 2 cardio you find fun (jogging, high incline walk, swim, dancing, tennis etc.). I find this helps keeps my metabolism going and I don’t have to fluctuate too much on my caloric intake (I personally prefer to eat about the same amount of food daily rather than change it for inactive days too much).
Orange theory seems more targeted at HIIT - you will not build as much muscle as you will tone and cut fat (if diet is correct). You may want to switch to traditional strength training and incorporate core exercises if you are wanting to tighten mid section as well as cardio.
Lastly, if you aren’t having fun definitely try something else. Working out and eating well is not sustainable if it’s a suckfest.
I just joined Ladder (app) this year and have found some great results with the coach of Team Limitless for building muscle and getting sets in. People in the program that do it 3x’s a week stack upper and lower body sets - otherwise it’s up to 6 days of planned workouts. I find the workouts are challenging but not so much that it isn’t sustainable. Deload weeks are built in every 6 weeks so you can give your body a rest. Overall it’s about progressive load and getting muscle gains. They follow pretty good guidence for getting sets in as another commenter was recommending.