Did you see a previous thread by OP? It's the second time they haven't let him out. The first time he didn't have an overstay. They just said he had too many covid visas.
One should only get a vaccine if they are in a risk group - old, with underlying conditions etc. Otherwise it's not worth the risk of possible side effects.
I wonder how they still manage to fly, without the proper maintenance and spare parts for the aircraft. That is very unsafe for all the countries that allow Russian aircraft into their airspace.
By "democratically" you mean with votes bought with Russian money? People said "no" to that illegitimate pro-Russian government. That is true democracy, the will of the people.
There is a clear defined rule for visa exempt countries - no more than 2 entries via a land border per calendar year. Some people are unaware of this rule and get justly refused entry.
I had the same problem there (almost 3 years on covid extensions), but with persistence and determination managed to cross the border. They have no legal rights to refuse you exit.
I didn't need to transfer stamps to another passport though.
The Laos passport doesn't have a limitation on the number of entries via a land border. The limitation is set only for the visa exempt countries, listed here: https://image.mfa.go.th/mfa/0/Svp1QKEi4u/migrate_directory/services-20161228-150522-918313.pdf