Vietnam used to have a 3 month tourist visa but when Covid came along the canned it and just ran with the 30 day TV. I understand the 3 month TV is being reintroduced August 15.
The whole event is a crock of...Vietnam is bringing back their 3-month tourist visa which I believe you can continually renew and which I will be doing. Beats jumping through a million hoops that Thailand forces you through. I'm well over it.