Internet dropping non-stop

Over the last year or so the internet will stop working multiple times a day. Sometimes there are spells where things are fine but as of late they’ve been terrible. I’ve now had three techs come to the house to tell me that things are fine. The second tech found a splitter in the box outside that he said he removed to give us a more direct connection. Things were fine for several months and then the outages started to ramp up again. As of two days ago we had another tech out who swapped out our modem and ran a diagnostic on things and said they were all within the threshold they should be. Everything seemed fine for roughly 8 hours and then the internet would drop and the modem would “reboot” itself. I gave up on it last night after the issue persisted and it’s done the same again tonight. Looking for some guidance on this because I have another tech scheduled to come out tomorrow and am hoping for a different response from the previous techs in getting the issue resolved. Any advice would be appreciated