What do I need to know about getting a 5-year extension for my AO X visa in Thailand?

Hello members

I have a AO X visa and been in Thailand just over 3 years. I got the visa through Sydney Consulate in Feb 2023. At that time the cash could be in the Australian bank, (and still is). My enquiry is, are there any members who have done their 5 year extension. Any problems encoutered. I have seen some negative results. I am planning to get the 3 million baht into Thai bank this year so its seasoned for at least 12 months any helpful advice would be appreciated. I understand immigration have varying requirements. I will do at Phuket office and visit prior to the extension date. Thanks for any input.