VPNs will always slightly reduce speeds due to the extra steps taken to encrypt and secure your data, but there are other things that might affect your connection speeds too.
Your physical location and your distance from the region you’re connecting to may play a part in this. If you are in Canada and are connecting to the USA region, your speeds will be faster than if you are connected to a region in Europe. Selecting closer countries should help.
Some security software will block Opera VPN. To maintain fast browsing, read the instructions from your security software then ensure that Opera VPN is white-listed (allowed). Some security software will constantly check Opera VPN’s credentials, slowing down browsing in the process, so white-list Opera VPN to ensure highest speeds even if you haven’t experienced an issue so far.
Finally, your router may be the culprit. If you find that your home WiFi connection slows your speeds, contact the manufacturer of your router. Ensure the settings allow OPENVPN connections for Androids and IPSEC connection types for iOS devices to ensure maximum speeds.