Hello @galb, Welcome to Connect. I'm hoping it doesn't take months to figure out what is causing your symptoms. Wondering if a vitamin deficiency might be a possible cause. Here's some information I found that sounds similar to what you are describing for symptoms.

"Vitamin B deficiency
You might also have a tingling sensation in the tongue and in your hands and feet. At the same time, you may feel very tired all the time, because both of these B vitamins are needed to make red blood cells and keep your nerves healthy. Low levels of these vitamins can lead to anemia."
--- Tingling Tongue: 9 Possible Causes - Healthline: https://www.healthline.com/health/tingling-tongue

Do you think this might be a possibility?