What is the best visa option for an Irish and a British national visiting Thailand for 90 days while also traveling to neighboring countries?

Hello : ) thanks for this super informative page. We (an Irish and a British national) are planning to come from our place of residence in Germany to visit family living in Thailand from December until March 2023 (90 days). During this period, we are also planning to visit Vietnam / Cambodia and/or Laos for around 2 weeks. What would the best visa option be? Get the 90 day SVT, if it is still possible? ( or is this only single entry?) OR enter Visa exempt for 45 days, travel to Vietnam / Cambodia / Laos then after reenter visa free to Thailand? Is it a risk to do it that way? Thank you very much in advance!