confused at “not being eligible for a CC”.
If over 18, you can get one from any CC provider. Doesn’t have to be your bank.
Debit cards work, but I’d NEVER use one online EVER!
If it gets scammed, then that card is (was) your only direct access to your bank account. At best, it’s 2 weeks of not being able to get any cash out of an ATM, or do chip+pin in Tesco.
Get a CC, set up direct debit to pay in full, and use that online. At least you have a buffer, and a back up solution, if something goes wrong.
(Speaking as someone who’s had CC scammed twice – once via a popular online bike store in NI, the other with a brand new card either booking via a hotel reservation website or via Paypal!).