there's a lot of people who contribute their time, effort and knowledge into making this group the go-to group on the inter-web for entry/visa/extension info to Thailand..
There's no one on this group that can tell you if you'll get out and back without issued after being here a year on an ED visa/extension 🙁
That is gonna come down to the officer at passport control you're standing in front of when you stamp IN to the country
AND
sadly, it is exactly people who were on ED visa/extensions that do have a lot of issues when they try to bounce out/back to get a new visa exempt entry.
The visa exempt entry is still 60 days (since july 15, 2024) and that's exactly why it's so hard to get out/back on them after an extensive entry/stay history.
I'd definitely cancel your ED extension from the immigration office that issued it before you exit the country (that shows you at least followed the correct immigration procedure when you are leaving)
Also have proof you're leaving the country again in 60 days <- the number of days you're gonna get stamped in for when you come back in free stamp / visa exempt because if they're going to ask you for anything when they let you in it's going to be proof you're leaving..
It'll either work and you'll get back in or it won't and they'll deny you entry. There's no middle ground and sadly no one on this group can tell you what way it will go. Even if you cancel your ED extension, have proof of onward travel in 60 days, it's still going to come down to the officer that you're in front of at passport control.
Best of luck with it (y) remember to cancel your current extension before you leave (because no matter what any one says just stamping out doesn't officially cancel an ED extension)
Do a transaction then update the bank book the day you go for the 90 day Non-O visa and it'll show the balance that day
Have the bank print you a 3 month detail transaction report (which is all that's required when you apply for the initial 90 day Non-O) on the spot when you get them to write/print the standard bank letter
At MOST offices that bank letter and the transaction report can be up to 7 days old and still be used