Internet speed suddenly lower.

Hello guys i have a problem with my internet connection.
I live in Greece and my internet connection is 100Mbps DL/10Mbps UL.
For the past 6 months i used to get 97 DL and 9.5 UL but now i only get 54 DL and 3.7 UL.
I bought new DSL and ethernet cables but they made no difference.
Also i reseted the router and contacted the technical support but they only gave me a link to a speedtest that everytime i take a test they get the results too automatically and told me to take 6 tests per day for a week.
My router is Sercomm H300S, my provider is Vodafone.
Speedtest results
In the screenshot i took the speedtest from a desktop pc connected with an ethernet cable.

Edited by deleted (Wed 23-Jun-21 20:36:20)

Sorry to say, most posters on here are based in the UK, so might not have experience of the service you are using.

The line stats - max achievabe, actual, attenuation, SNR, errors all look good.

Potentially it coudl be your PC, do you have any AV software running?

Can you borrow another PC to see what happens?

In reply to a post by MHC:

The line stats - max achievabe, actual, attenuation, SNR, errors all look good.

Potentially it coudl be your PC, do you have any AV software running?

Can you borrow another PC to see what happens?

Also the OP doesnt say who else/how many other devices are using the connection at the time of the speed test, so potentially there could be streaming going on or downloading being done that may affect the speed test result.

Could potentially be the router, swapping it for another one might also be an idea?