PPPOE performance degradation

Hi! I’ve got a RB951-2n running 6.48.3 with a PPPOE client to the ISP (gpon connected)
I am noticing degradation of performance over time - initially connection is about 100 mbit, however over time it slows down to 10 mbit or less. Re-establishing the PPPOE connection fixes the problem. Not seeing anything obvious in the logs. Any ideas in which direction to investigate? Other routers (tp-link and other rubbish) do not seem to have the same problem

My main guess would be - is traffic building up overtime causing congestion on the link?

MIkrotiks can run a vast array of services if not secured correctly will end up being used for amplify attacks and other things. A copy of your config may help us - but I’d be checking throughput on the ppp interface when the service starts running slow to see if there is an abundance of background traffic causing you issues.