Valencia is nice. I'm not sure about rentals there. Airbnb is expensive and geared towards tourists mostly. We got lucky as my girlfriend has a lot of friends here and one of them was moving to Australia so we leased directly from her. But check out some of the Facebook apartment pages for each city. I think there is one for most cities in Spain. Madrid and Barcelona are very expensive for rentals because a lot of tourists there.
I'm not sure where you are looking at Coleman coolers for $1080? That is too expensive. You can go on Mercado Libre and find some 100 qt coolers for 553,000 pesos.
People and culture are excellent. Safe too. No cons at all so far. Some cities have some anti-tourist sentiment but it is only a few people that are causing issues.
You can get a digital nomad visa here and pay 15% reduced taxes. I haven't had to file taxes yet. I work remote so I need to see what the cheapest option is but my accountant before moving here told me applying for a digital nomad visa and paying 15% would be the most efficient. My girlfriend has a Spanish passport. She works online but she works under the don't ask don't tell when it comes to taxes. In Argentina she was working remote and was declaring a small portion of it.