.. and I realise my reply is not helpful in its own right.
If you're suffering suspected performance issues, may I suggest you:
1) set up a BQM at
https://www.thinkbroadband.com/broadband/monitoring/... and share a graph after a day or so
2) perform some speed tests using a modern, device without any other active devices on your network, using a wired connection to the router. Speed tests from Thinkbroadband or speedtest.net are generally the most useful in my opinion
3) Give an outline of the actual problem you're seeing, and whether it's permanent or intermittent
Traceroutes to/from different sources to different IP addresses don't really help diagnose anything in this situation,
FWIW, Vodafone broadband isn't known for being the best performance, but if cost is your primary driver - as it would appear if you are on a social tariff - then it's not reasonable to expect gold class service. Saying that, the connection should still be functional and you shouldn't regularly need to revert to mobile data as a fallback.