Data packet loss? How to fix it

Hey, everybody,
I'm facing this problem - constantly missing the icon of Internet connection, as well as there is a clear loss of data packets. A familiar specialist advised me to change my Internet provider, also said that my traffic can be monitored.
I have a direct connection, not wi-fi, but cable.
Can you tell me what the problem is?

It can often be a router issue. Most people just stick with whatever vanilla router their ISP gives them. It might be worth looking into something beefier like a Fritzbox: https://en.avm.de/products/fritzbox/

You can use glasswire to monitor your computer and check the packet loss, but if it happens only in your computer or also with any other device, check on the speedtest of cloudflare there is a section that indicates the packet lost and try with your other devices if it happens in all of them is the router or your ISP if it only happens in your computer check with glasswire and see what is using all the bandwidth, reset connection, antivirus, extensions, something working in the background, a cracked free program you recently installed and notice unusual traffic.

Art of old school pinging is lost.... Open cmd (windows key, type'cmd', or windows and R) , type or copy-paste:
ping -t google.com

you'll see when packets are not reaching destination.
It can be cable issue, simple as that.

does the issue replicate on every device in your home network?
could be your dedicated nic. buy a nic adapter and install it into your motherboard.
could be your router going bad. replacing it could be a possible remediation.
inspect your ethernet cable for any damage / replace it.
blaming the ISP? give customer service a call and inquire if there's been any service interruptions. the modem/router is usually their hardware that they are leasing to you. most cases they will come out to replace it for free if you complain.