No problem you can just apply for a retirement visa because you have the correct amount of money.
I would suggest you go online to the thai embassy website and apply for a retirement visa and it will tell you all of the documents you need to get together. You need to submit the documents and wait for your appointment at the embassy and if they need anything more from you, that can be done at a later date.
Yes, a condo contract is definitely a proof of stay but you may need to provide also the owner certificate. They may ask what date you intend to return or they may ask you for a flight ticket. It is often different requirements in different embassies or you could apply online.
I think from what I have read a lot of people have submitted multiple statements that don’t have the correct amount in one bank but if you total them all up they do