How many entries or length of stay do I need for my visits to Thailand as a British citizen with dual citizenship?

Hi guys, thank you to add me here! I have a bit weird question! I have dual citizenship from UK and Russia. I know by now it doesn’t matter because of the finger prints. But I want to have your advice. Basically I’m British citizen and tax resident too. But I come to Thailand once a months and stay for a month then I have to go back to the UK for work( I’m self employed). So, it’s around half a year. Do you know, how many entries or summary stay I’m allowed or it depends of the officer? Don’t want to do elite visa because not sure what happens in three years. Some of the people said I need to have prove of money and return ticket and just show on the border. Is that right? ( the reason I’m asking is I have a relationship in Thailand)