I've been living in Thailand for around 12 years and I'm only 37. Never been denied entry, and rarely been ask proof of fund or onward ticket. I simply avoid BKK and Phuket airport, and Poi Pet land entry. You can enter from anywhere else very easily.
There is no long term visa for you unless you get married (which I did). You are too young for retirement and ed visa is less and less of an option. I did visa exempt and tourist visa for 8-9 years. I got married in 2022. So you can still do a mix of visa exempt and tourist visa and be okay but find a wife asap, since you are young you have no other long term solution. It's getting pricier every year to use agent for ed visa or business visa, and never know went they will crackdown again like they did with volunteer visa.
Do not listen to anyone who haven't done a border run in over 20 years. Old dude love to patronize younger people here with awful info just to make you feel guilty. I'm 37 and have been living in Thailand since I was 25. I'm married now but I'm very familiar with a lot of the border. I live very close to Nong Khai border. Getting denied by land is not a thing in your situation unless you try Poipet which are notorious for bribery. The big 3 to avoid are Poipet, BKK and Phuket airport. The rest of the country is still easy to enter from.
You have received mostly bad info so far (from Kool, John, etc). There is no such thing as getting denied entry by land except in Poipet. You have done 0 border run in 2024 so you can still do 2 by land. Every time someone come up with anecdotal evidence that someone got denied, it's one of three things: 1) Poipet ; 2) It was his 3rd attempt in a calendar year, or 3) A border officer asked for proof of fund or onward ticket and that person didn't have it. It's never due to something else. If you border run Nong Khai or Mukdahan, they do not ask for any proof of fund or onward ticket, so I usually go there. Keep in mind that BKK and Phuket are strict, but these are by air and doesn't apply to what you want.
Everyone know that, but this isn't the topic discussed. The topic is about you wrongly stating that "an overstay stands out in your passport like a fart stain on a wedding dress". This is what I called "factually incorrect", because it is.