pretty sure I stated that when referring to “unique” but you mostly find they cut their fees to zero but not the Thais atms fees. Cash is also a good option for people wanting to get the best rate possible.
You can extend at immigration for a further 30 days without any issue. You can then do a border a bounce by land , receive 30 days and extend at immigration for another 30 giving you 120 days in total. Without too much hassle. After this there is no concrete written laws, it’s up to the immigration officer, luck etc. if your a genuine tourist and travelling in the region for touristic things it will be a lot easier to prove. If you plan staying longer than 6 months on Thailand it’s probably best looking into ED visas or what else is available.
last time I was questioned before I simply showed them my travel plans and nice places I’d visited and they could see I was genuine long term tourist. People up to no good or working illegally normally struggle to provide these things.
The last two friends I spoke to who entered Thailand were both asked for onward ticket when they arrived in Thailand. Both people had been out of Thailand for over 6 months but had visited multiple times in the past.