Sorry, it took me this long to reply. I was not clear enough on the Op; I only assume there are 30 wallets, which I don't think they are up to, but they are above 20 wallets, and these wallets are controlled by one private key. Electrum gives me a lot of wallets to be used, and new ones can also be generated if I want.
So the transaction is spread across all these wallets. Some receive two-time transactions from different senders, while others receive only a single transaction. If I send them to a single wallet, the size might be too large and more expensive, which was the reason for my question.
Good to hear that you have actually got your problem solved,
It seems you are mixing up some terms here, although it is technically possible to generate two different wallet with one private key or seed phrase but in this your own case it is not 30 or 20 different wallet as you have put them out but rather those where addresses. With an HD wallet you can have master private key which generates extended or child private keys and then public key which in turn generates addresses. So what you actually have is a master private key and those were addresses and not different wallets. This master private key can also generate more than that 20 addresses or even more than 30 addresses as you thought it couldn’t. The reasoning you’re seeing 20 of them is because of your wallets gap limit which is set at that number.
The way it works is that once a new address receives bitcoin then a new wallet is created. For example of there is 20 free addresses there (those that haven’t received any bitcoin before) then one of them receives bitcoin, another address will be created to make them 20 free addresses again. So on those addresses the reason why you saw particular address that received more than one transaction appearing like it’s a separate thing is because bitcoin treats each received transaction as an UTXO and even if one address received 10 separate transactions it will be 10 UTXOs on that same address and when sending everything from them they will appear as 10 inputs and not one input.
