I want to be able to download apps without using a payment method

See -> If you can’t download or update apps on your iPhone or iPad

If you can’t download or update apps on your iPhone or iPad – Apple Support (UK)

scroll to point 2  ⤵️

Add a payment method

You may need to have a valid payment method on file, even if the app you want to download is free.

Add a payment method

See also -> Payment methods you can use with your Apple ID

Payment methods you can use with your Apple ID – Apple Support (UK)

fyi: Not all credit & debit cards seem to work with App Store / iTunes Store, try a different one, or preferably a credit card. If your card is not accepted as a paymenf method, you need to contact your bank.