I was also recently looking for a car rental at Tenerife Airport without a credit card, so I totally understand you . Most large companies do block a deposit, but I found a good option through
https://rentcarfy.com/car-rental-tenerife-airport/ they have a special section called Car Rental Tenerife Airport no credit card, where you can choose a car without a deposit and pay with a debit card or cash.I booked through this website in September, and everything went smoothly — no hidden fees, the car was delivered quickly, and customer support answered all my questions before I arrived. The main thing is to choose the option with full insurance, then you won't need a deposit at all. It's very convenient if you don't want to deal with having money blocked on your credit card. The service really works, and I can confidently recommend it.