VPN speed has recently improved for me. Almost no speed loss.
Also use wireguard instead of openvpn it’s faster
Damn ! In my case I drop from 1 Gbps to 330 Mbps in France, no matter which server you choose in France or neighbouring countries 
I use wiregard, but I have to check if I use UDP or TCP
Edit: it is WireGuard UDP…
Download speed is always good but upload speed is the worst of some country servers.
Openvpn TCP works best for me from the UK using 5G no buffering with multiple devices connected for hours at a time.
How? I only get 40Mbps while I have 250Mbps without protonvpn. I use quick connect, which connects via WireGuard (UDP). I tested on fast . com (Not p2p)
It’s pretty impressive. I am getting similar results in New Zealand. I am even able to play online games with only a few ms of latency that is effectively unnoticeable. I must live close to a server! It is night and day compared to a few years ago when I would have had to use split-tunnelling.
If you are getting the same speed on or off something is wrong and you should report this. It could be something unrelated to the VPN you are using like recent Trend Micro man in the middle exploit. Whatever it is it would could be helpful to let Proton know that you are experiencing this behavior. Note the server IP address and times. Protocol used and switches. Ethernet or WiFi. And the general state of your firewall and DNS server used.
Same. ProtonVPN has really good speeds.
Yes I use WireGuard UDP all the time. Don’t remember the last time that I used OpenVPN lol.
Payed or free servers?
I am sams as you but from Australia.
Tested all protocols, on both TCP and UDP actually all are very good, but Openvpn TCP is the best for me.
Are you on the free plan or using a really slow device, that could explain your low speed.
Otherwise I would manually test every protocol, including TCP and UDP, and on different servers. (For me OpenVPN TCP works best because I have a shitty router.) There are so many factors that could make one protocol work better than the other, such as: Network conditions, Firewall, ISP (Throttling), Device performance, Router MTU size etc.
Most people use speedtest.net for speedtesting.
Try Wireguard TCP. A little bit more overhead, but blends in more than UDP. ISPs are less likely to muck with/shape your traffic and you’ll likely get fewer capchas. Led to a slight overall improvement in speed, IME.
Yes I find sometimes UDP can be sluggish on public WIFI but TCP is always rock solid through Openvpn.
Yes, personally if I wanted to change protocols, I only use stealth (it also uses TCP).
Stealth is excellent and is very stable. I mainly use Openvpn connect on Windows with TCP country configs.