What are my options if I have a Non-O visa but will delay my entry into Thailand?

for a single entry non immigration O visa ( not retiring) do you have to have 400k in your thai account nowadays? i want to visit for 90 days and not have to mess about doing a border run after 60 days

Also, you can't apply for a Non-OA in Thailand, only a single entry Non-O.

You misunderstand how the Visa itself works.

You have a Visa that is valid for 3 months from the date it's issued. That means you have that long to enter Thailand on the Visa and when you do you get stamped in for 90 days, even if you enter on the very last day the Visa itself is valid for you will still get 90 days on your entry stamp.

Print out the PDF that is the Visa and present it with your passport to the officer when you step into the country.

You will be stamped in for 90 days