If someone asks me which of these two coins I would invest in, I would choose Polygon (MATIC).
The reason is simple: XRP has a supply of 100 billion, while Polygon has a supply of 10 billion.
A coin with a 100B supply is currently trading around $1.9, whereas a coin with a 10B supply is available at around $0.11 at the moment.
If I buy XRP and hold it for the long term, due to its huge 100B supply, even with strong momentum it is unlikely to go beyond $6.
But if I invest in Polygon at $0.12, and Polygon reaches $1, my investment would become 10x.
So in comparison, XRP offers around 1x potentia