Okay,update:
For going to Tachilek, Myanmar.
At the border ( Mea Sai) they warned me that at Birmese side they require proof of vaccines or negative test.
Because I didn’t have that and I’m not vaccinated they said to go to the hospital.
So I went ,it’s 1.9 km from the border on the right side.
Kasemrad hospital .
The test costed 250 Baht and took one hour.
A test done outside,a nurse in a cabin who sticks her hand through a long kind of plastic glove and squeezes a stick into your nose.
Then I went back to immigration.
They needed 1 copy and the Birmese side also needed one.
So I had to get out again and directly right of the immigration is a copy shop.
2 copies : 6 Baht.
Back to immigration they stamped my passport and let me go.
Crossed the bridge and was awaited by 2 nurses and 3 guys who needed my proof of vaccines or the negative test at some testing area.
So they took one copy.
Next they stopped me and asked how long I was going to stay.
I said one week and they showed me in a small office where they took my passport and printed a Burmese permit of stay.
They also took a picture which ended up in that Birmese “ pasport”.
It costed 500 Baht.
Then I went out and a bit further I had to show my Birmese “ pasport”..
It was a bit messy and they took my suitcase through some kind of x ray portal,like they have in airports.
They asked me to open my suitcase and looked a bit in it,and was free to go.
The last part there were police in front of their office who wanted to see my “passport “….
again!
I gave my Burmese one,and they asked for my real one.
To my big shock I couldn’t find it.
They must have kept it in the office,i said.
Oh yeah,no problem.
Pfffft.
Then in the end ,I was in Myanmar.
Took like half an hour from Thai to Birma maximum.
Mingelaba!