I’ve not tried it before, but I’m getting speeds of 35-50 Mbps from proton’s free VPN which has good reviews for privacy and speed.
The free version allows using 10 locations. It auto-connects to whichever it thinks is fastest but you can pick one of the other 9 if you prefer.
Unlike Opera, this seems to apply to the whole of the machine not just the browser. There might be disadvantages in that if apps that run outside the browser expect a consistent location. But the VPN can be instantly enabled or disabled via its control panel on the taskbar.