Can I do one more border run in Thailand before needing a new visa?

Above is good advice, however Id advise you to get the visa paperwork rolling asap, the less stamps in you passport it seems the better these days. But saving one border crossing is a good idea. Im glad I did that.

You should be able to do three more if you do your next one in December. It's two per calendar year- so you do another in December, then February, then the final one in April. That will bring through to June before you'd *have* to look at some other option.

This depends on the border but Nong Khai usually sticks by the letter of the law if that is your nearest border.

One consideration with this maximalist plan is that it may be advisable to "save" at least one visa exempt land entry in case of issues with a subsequent visa, so you have a fallback option. If you did use them all up and then were rejected for a visa in June, you wouldn't really have a plan B to come back and get your stuff in order.

Yes, OP can do one more run this calendar year.

not really understand the question, but if mean how many free Visa Exempt Entries you can do before you have to spent money on a visa, it is unlimited, with as mentioned 2 times a calendar year by land borders and limited by immigration officers who will tell you that people who like to spend long time inside Thailand need a visa that fits your purpose of stay.

As long as you don’t do more than 2 land borders a year on exempt