Yes, it may be possible in some cases. However, having a UK ETA does not automatically mean that you can open a UK bank account.
A UK ETA is an electronic travel authorization for short-term visits. It does not grant UK residency or long-term immigration status.
Whether you can open a bank account depends on each bank’s requirements. In general, you may need a passport, proof of address, and additional identity verification documents.
If you plan to open a UK bank account after entering the UK with a UK ETA, it is recommended that you check the account opening requirements of your chosen bank in advance.