Just do a border bounce with one of the agencies in Maenam. Cost is around 4500 baht. They will check your paperwork before you book and it’s guaranteed visa for 60 days which you can extend for an additional 30 days on samui. Super easy just means a full day in a van.
There are agents in Pattaya offering the DTV for 100k thai baht approx. You only need passport and photos but you have to go to Laos to get the visa. Could be a good option for you.