As with most online multiplayer games, it is recommended that you have internet speeds of at least 10 Mbps to play Valorant. Most games do fine on 1 to 3 Mbps so 10 Mbps gives you plenty of room for the VPN to slow down your connection slightly (which even the fastest VPNs will do).
Although the faster your connection is the better it will probably be for playing Valorant, there is no need to stress if you are paying for slower internet. You can still try a VPN using its money-back guarantee. Our recommendations should not affect your speeds much because they are specifically designed to be fast for gaming and HD streaming.