Do they accept Mir cards in Patong and can I withdraw money?

No, of course not. Due to sanctions, Mir cards do not work almost anywhere in the world except for a few countries, but Thailand is not among them. Therefore, neither in Patong nor anywhere in Thailand can you pay or withdraw money with a Mir card. For more details on everything you need to know about currencies, money, and plastic cards in Thailand, read here - https://nashaplaneta.net/asia/thai/valuta-dengi-v-tailande

Where to go in Thailand for the first time?
Do I need a category "A" license to rent a motorbike?
Can I exchange rubles in Phuket?
Follow the link, all these questions are discussed in the chat - https://t.me/thailand_travel_chat