Leave it.
It's wood and unfortunately in a warm house it's buckled a bit but that's a bit of character.
Start sanding you could ruin it.
I remember working for a furniture salesman that had a massive oak table that was a return because it had a crack and a bit bent.
Looked fine though.
Most of his furniture was faulty especially the wood which had been returned with fault, but he said that's wood. It happens.
If you want to do something with it then sanding may turn out uneven.
Then you may need french polisher. May be consult one before you tackle it
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