I would have loved to emigrate to Australia, and have visited family several times, and found the lifestyle to be as wonderful as I imagined. But am an only child and knew that I couldn't leave my parents in the UK. I too have resented being in that situation. However, having lost mum last year after a long illness and lots of caring, and being a bit older/further down the path than you, I can now say that I don't.
I think whilst there is still the hint of a hope that you could go and lead that life, the frustration, the niggling doubts remain and they are quite undermining. Now there is no hope of me going, then I have found there is now a sense of lightness, a lack of doubt. It's quite liberating. I am glad that I stayed to look after Mum. We had quite a tense relationship all of our lives, but we grew much closer in the last year. I am glad that I am here for Dad.
Yes, in another life, I would have had a house with a swimming pool, friends round for barbeques or evening meals on the veranda, and my kids wouldn't have been half so cold and muddy coming home from football/rugby - and let's be honest, tennis and cricket most of the time too. They would be tanned, fitter and used to an outdoors life.
But life isn't bad. The UK isn't sunny, but it doesn't have wildfires. And once the stress of caring for your parents is over, you can find joy here. Walking amongst spring flowers this year has been magical. Crunching through autumn leaves, then coming home for hot chocolate and marshmallows is brilliant. But don't underestimate the impact that those caring responsibilities have on you every day. As an only child (of only children) I knew that they would be there. I had no other support/cousins/aunties etc. But I didn't realise until recently how much they had weighed on me.
Look after yourself whilst caring for your folks. I know how hard it is to really relax in this country, knowing the phone could ring anytime. Once CV is over, try to plan yourself a week or two in the sunshine, or on a skislope, if that's your thing. Arrange carers for a week or two a year (or ask your sibling to cover that cost) and get away. Watch trash telly for you, when you can, if that is your thing, or get a dog, or take art classes - something that it just for you. Ask your GP to go on a counselling list for yourself to process all of this. You can't have the dream life you hoped for. But you can have a life, and treat yourself well. I totally understand them but don't let the doubts/frustration get you down. x