Visa runs + extension + non-visa entry will lead a lot of the IOs who are processing your entry to get suspicious. You’ll be pulled aside and if you don’t have proof of onward travel, 20k THB in cash and an amazing explanation then there’s a decent chance you’ll be turned away.
There’s also some unwritten rule right now that 180 days per calendar year is the maximum, but I don’t imagine that’s the case if you use an agent service to fast track your entry.
She can do a border bounce with an agency that takes her to and from the border. They grease he wheels at the border, usually Cambodia so it is effortless.
BUT
If you do a border run, it is very frowned upon by immigration officers when entering via air, expect a high level of scrutiny from them if you get the wrong one and there is a chance you can be turned away.
The same agencies that do these border runs also sell safe entry services at airports to avoid this scrutiny. Same concept, they make it hassle free to re-enter.