Looking for a device to run a slideshow / webpage on TVs
I'm looking for a device which can run a slideshow across multiple TVs in a few different sites. The slideshow is just webpage but has some dynamic content and animations, it currently runs on Amazon Fire TV sticks fine (it could be smoother performance-wise, but it's acceptable).
I recently moved one of them to an old Raspberry Pi Model 3B that I had because I wanted to get away from all the Amazon branding and adverts, also so that I could run some scripts like making it reboot daily, crash recovery etc. Again, runs fine on the Pi, about the same as the Fire Stick. I also tried a Raspberry Pi 3A+ but it really struggled to run it at all.
I'm needing to expand to more sites so I need to decide what devices I buy, ideally I want to avoid sticking with the Fire Sticks but they seem to be the most affordable. The Raspberry Pi is so expensive now, once you add all the needed extras (case, power supply, SD card, HDMI cable) the Pi 3 Model B is nearly £70, which is hard to justify when the Fire Sitck is £40. Are there any other affordable options that give me the freedom to run what I want as the Pi? It also needs to fit behind a TV.
Edit: should specify if it wasn't clear from the £, I'm in the UK