I assume this is NBN FTTP and not another FTTP network like Opticomm or Places Victoria?
Ok an indication of backhaul congestion is time of day. Most likely times for this to appear is late afternoon after the school kids get home right through to about 10 or 11PM, sometimes with a letup in congestion about dinner time.
With the worst providers it can also be mornings around breakfast time as everyone does their email and social media checks before school/work.
Mostly avoid the real budget RSPs like Dodo, Belong and Exetel. They are cheap for a reason. Yes I know belong is owned by Telstra but it is the budget arm so backhaul bandwidth for Belong seems to be more constrained from some anecdotal evidence on Whirlpool.
However even budget RSPs can be ok depending on which POI you are connected too and the demographic of the RSPs users on that POI.
Try to avoid long term contracts is the best advice I can give as this allows you to jump from RSP to RSP easily. FTTP makes this so easy as you have four UNI-D ports so you can provision a new service on an unused port whilst maintaining the old service on another port. Once the new service is up and running you cancel the old service so no internet down time.
A few RSPs worth checking out that you may not have heard of are Skymesh, AusBBS and Nuskope.
All three are starting to gain in popularity on Whirlpool because of good service and decent backhaul.
However you will have to check if they service your POI as Skymesh at least is not fully national as yet.Go to the full post