Haven't used this but it seems like a popular choice:

Samsonite Underseat Spinner

https://www.amazon.com/Samsonite-Spinner-Underseater-Port-Ocean/dp/B07H8TX91R/

Edit: another option

https://www.amazon.com/Travelpro-Luggage-Maxlite-Lightweight-Suitcase/dp/B07BL4XRQ2/