Can I leave Thailand with a 3-month retirement visa and return to extend it to a year?

I've posted a couple of times on here about Immi asking me for proof my 800k funds originally sent in 2019 came from abroad. I have something to note and something to ask. To note, I asked my bank on two occasions to supply the proof, they said they couldn't find any origin abroad deposits. So I was faced with importing another 800k. Then this week I found my old bank book, and sure enough there was the record with the FFS code for a foreign origin. So, note that the bank may not try hard enough, you may need to push them if you no longer have your old bank books. Second, is a question. I can now apply for the retirement visa here, but I'm heading back to Europe in April. As I understand it, I can get the non-immi retirement visa now, valid for three months, then extend it to a year. My question, after getting the 3 month visa, can I leave the country with a re-entry for a few months, then come back in and apply for the 1 year extension, or will my 3 month visa become invalid upon departure?