What are my options for extending my visa in Thailand given my financial situation?

Good afternoon. I entered Thailand with DTV in august 24. so i need to extend. I applied under medical soft power and already printed all documents from Bumrungrad hospital. Due to high medical costs and co-pay from insurance, my foreign bank account can’t keep the same balance for months. I printed evidence of income with embassy signature. But if they still want to see a steady balance, I could print a sponsorship letter from relatives. I believe this was meant for emplpyers. Did someone try private sponsorship? I don’t like long bus trips and would prefer to avoid border jumps 🙏