pull out your old phone jacks and follow them through with CAT6
If you’re lucky, you may not even need this step.
Buying 4-pair cable in Cat5e-or-better spec has been cheaper than 2-pair Cat3 “phone cable” for probably around 2 decades now, due to the vastly higher quantity of it being manufactured, so in plenty of newer houses the phone lines are wired with it.
You could still get unlucky and find the jacks are daisy-chained, but having a central wiring panel where they all connect to became popular in a similar timeframe.
Bit of a long shot, but in the best case scenario all you need to do is replace the jacks.
If you’re lucky, you may not even need this step.
Buying 4-pair cable in Cat5e-or-better spec has been cheaper than 2-pair Cat3 “phone cable” for probably around 2 decades now, due to the vastly higher quantity of it being manufactured, so in plenty of newer houses the phone lines are wired with it.
You could still get unlucky and find the jacks are daisy-chained, but having a central wiring panel where they all connect to became popular in a similar timeframe.
Bit of a long shot, but in the best case scenario all you need to do is replace the jacks.