Internet connection coming and going I have Xfinity internet 600Mbps

On January 26, 2022 at night I completely lost internet connection and all the lights on the cable modem right router were on and green I restarted my router and had internet connection again but I called comcast anyway and they sent out a technician on January 28, 2022 the connection worked fine after I restarted the cable modem router but right before the comcast technician showed up I lost the internet connection again well the technician did all the examination, I saw through the window that he installed some stuff on the line (looked like cables) he came and tested the modem went back outside to adjust a few more things then came back inside tested the modem again and told me the internet should be working I tested it and sure thing it was working the technician told me that the signal was very bad or something like that  After the technician left the connection worked fine the 28 (the day the technician fixed it), and it worked fine the next day the 29 but on January 30, 2022 my parents were in a zoom meeting and the internet connection started going bad it was in and out I had connection but the zoom was struggling they had an error that said internet connection unstable I looked at my modem and all the lights were on and green this issue happened at 10:00am and lasted until maybe 3:00 pm so I called comcast and everythinh was ok on their end so I decided to upgrade my speed with them from 300Mbps to 600Mpbs after I did that upgrade about 20 minutes later the zoom meeting was way stable and everything was fine until 4:00pm I lost internet connection and again the lights all lights on the cable modem router were on I looked at my xfinity account and it said everything looks good so I decided to disconnect it from the power and plug it it again and that seemed to fix the problem I haven't lost internet connection at all since then, I dont know how long it will last like that I just really want to know what is going on I do have an event log picture from the morning of January 30,2022 I will attach it maybe someone can tell me why this has happened to me so that I can prevent it. Thank You All For Your Help!