The individual display types are always specified within the iPad device specifications - which can be found on Apple's website.
Retina and Liquid Retina are Apple trademarks that describe screens that have very high pixel density - where individual pixels cannot be individually discerned with normal eyesight. Such screens are typically 264dpi (dots/pixels per inch).
The only iPads that have miniLED backlighting are the fifth generation (2021) and sixth generation (2022) iPad Pro 12.9. These are known as Liquid Retina XDR displays.
The just announced 2024 models of iPad Pro, with 11" and 13" screens, have Tandem OLED screens - known as Ultra Retina XDR displays.
All other models of iPad have conventional LCD/IPS screens that feature standard (edge-lit) backlighting.
iPad screen refresh rates are typically 60Hz. High-end models can increase the screen refresh to 120Hz (for smoother scrolling), or operate at slower refresh rates to save power. Screen refresh rates are not related to screen-flicker - the latter not being an attribute of modern LCD and OLED screen technologies.
If you need help selecting an iPad for your specific needs, you would be best advised to consult a product specialist at an Apple Store, or contact Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page.
Alternatively, you can initiate and manage your support cases from Apple devices using the excellent Apple Support App. If not already installed, the App can be downloaded from the App Store:
https://apps.apple.com/app/apple-support/id1130498044
