What are the best options for long-term stays in Thailand after receiving a warning on tourist visa use?

Just as a data point, recently got a stamp on my tourist visa in Vientiane that says I may be refused future tourists visas because of traveling to Thailand multiple times on tourist visas.

To give more info, I usually stay in Thailand about 7 months out of the year, with multiple trips, and often long stays in other Asian countries. Bangkok is my home base for area travels. Don't work while here. Never overstayed and have only 1 tourist visa (single entry) per year. The rest is just visa-exempt entries and sometimes extending stays at Chaeng Wattana.

I have a US passport and I have the version that has 51 pages rather than the standard 25, because I travel a lot. So there are several stamps over the last 6 years that I have had this passport. In fact it's only got a few pages left because of how much I travel and will need to be replaced soon.

I haven't broken any rules or gotten into any trouble with any Thai government agency ever and I love spending the months I'm not working in the US in Asia, with my home base being here.

Any suggestions on the most reasonable way to proceed? Should I just be doing visa-exempt entries? I'm worried that no matter how I play it here they are looking for people to "crack-down" on. Switch to an ed visa for the next couple of years?

Thanks in advance for your recommendations.