OP that sounds so hard, I can empathise with how claustrophobic it feels and how you spend your day just trying to avert a tantrum.
Good things - routine looks great and at least you're getting some down time during naps and evenings. I agree it's probably time to move to one nap, how about reducing the morning nap by five mins each day rather than going cold turkey? My DD is 16 months, she's awake at 7, asleep at 12 (I feed her early) for 2h, then asleep again at 6.30-7pm.
It does sound like DD is frustrated, I can also understand how isolating it feels to not have support around you.
Regards support (which sounds like the most important thing right now):
There's absolutely nothing wrong with using a childminder or any kind of help frankly under any circumstances. You do what YOU need to do. Let's face it, the help is in the absence of a support network or your DM/MIL... I pay for help at home as a SAHM, if I didn't I would have no one. People who have family support often take it for granted, don't feel guilty, it's not your fault and we all need a break esp if DH is away so much. Would there be any chance of asking anyone to come and stay at anytime?
If childminder is not an option regularly for you, do you have any playgroups you can attend with DD where you can sit back and let her play? Even if you could have some time out in that environment it could be a help. You could also meet some other parents who are likely in similar positions and can at least lend an ear. You may even find someone who has a teenage daughter who you could invite in to play with DD whilst you were in the house, st least to occupy her and give you time out, you could pay a small hourly wage which would reflect their age / experience
Regards frustration, how about using a picture board with DD to help her to communicate what she wants? For example - when you wake up show her a picture of breakfast so she knows you're going to have breakfast, let her choose (between 2!) her clothes and maybe cereal for example if you have to. When you're going out, let her choose between eg pictures of park and shops, or at least show her a picture of the shops when you're going.
Leave the pictures in an accessible place so when she wants something she can point to it. You can easily print anything you need off the internet, introduce a few at a time. Might help to bridge the gap between now and talking.
I hope someone with more ideas will be along soon too, good luck