You probably get a better answer asking Chatgpt to summarize some points for you, I would say Google it but since you came in to the forum asking, then you probably are too lazy for that 
Network size nothing to do with how many transactions get handled. That is all programmed into the network rules. Whether its 1 computer or 1 billion computers in the network, all transactions must fit into 1 block of data roughly every 10 minutes. So on average that has been improving over the years because transaction sizes keep getting more efficient in the amount of data (bytes) it takes up in the block.
https://www.blockchain.com/explorer/charts/transactions-per-second says currently above 4 per second.
Network size nothing to do with how many transactions get handled. That is all programmed into the network rules. Whether its 1 computer or 1 billion computers in the network, all transactions must fit into 1 block of data roughly every 10 minutes. So on average that has been improving over the years because transaction sizes keep getting more efficient in the amount of data (bytes) it takes up in the block.
https://www.blockchain.com/explorer/charts/transactions-per-second says currently above 4 per second.