I read on SO that there is no min limit - just a max limit of 128MB - for a block.
Bitcoin blocks have a max weight unit of 4MB, not 128 MB. Blocks that large (128MB) would lead to extreme network centralization due to a need for high-end hardware to run a validating node... but anyways.
For example if a miner always takes a single transaction and creates a block from it, he probably will be faster as most other nodes and will gain most taxes or not?
No, the number of transactions in a block has no bearing on how fast the block is mined. Putting more transactions in a block does mean that the merkle root computation will take a little bit longer, but this calculation is done in parallel by the miner's bitcoin node, not by the mining hardware itself. So a miner does not have any advantage/disadvantage in mining a large/small block.