There is no salary requirement... have your 500k available for atleast 3months, meaning cash, saving account, or whatever is the correct word in english :) No stocks, cryptos or so
Many people gets asked about latest payslips, there may be many reasons for that. One being (only my opinion) to verify you actually work for the company if you apply for workcation. Other being (i think not likely the reason), can you support your stay in Thailand