Line dropped then reconnected at less than half the speed

[#1]

Was at 1MB/s until 21:00 when the line just randomly dropped and reconnected at less than half that speed.  Can't even watch a  short 5 minute Youtube video without sitting and waiting for it to buffer for 10 mins. 

Phone line is quiet and nothing has changed on my end.

[#2]

Then report a Broadband fault, as advised about a month ago.

[#3]

Assuming your landline is with Plusnet, use a mobile to text to 07800 008121: PHONE <landline> 

If landline is with BT, text to 61998: PHONE <landline>

Where <landline> is the number of phone line you want testing. If a landline fault is found it should be actioned automatically.

[#4]

@jab1  Which was done and nothing came of it.  No reply, nothing.  World class customer service. eh?

Is this acceptable in 2023?  

You can''t even open a vast majority of websites, let alone watch any of the streaming services we PAY FOR.

[#5]

@Azagoth From that data, you definitely have an issue -Downstream SNR of 15.5dB indicates the DLM is struggling to maintain an acceptable level.

Do you not have the option of FTTC?