Can I return to Thailand through land borders after obtaining a tourist visa in Savannakhet?

Be aware that you need to provide copies of a minimum of 3 months bank statements by photocopy ,,,also they might ask you for evidence that the copy you presented came from your email address ,,so at least a Lao SIM card needed ….you can go overland back to Thailand ,,very simple from savannakhet bus station ,,about 1-1.5 hours to clear both sides

The 2 times at a land border per year only applies if you're entering without a visa.