WiFi Reception Weaker Over Time?

[Android Central Question]

I'll cut to the chase.

Lately my phone's reception of WiFi has been absolutely terrible lately. For instance, when I'm in my room, I used to get at least 3 of the 4 bars indicating signal strength. Apps would work fine.

Now, I'm lucky to get even 1 bar in my room, causing no apps to function properly.

I know this is a problem with my device and not my connection because other devices in my room still function normally, AND (here's the real nail in the coffin) I can stand right next to my router, like I am now, and receive no more than 3 bars at BEST. I am from Hawaii and I googled about my problems and searched few local stores and found TCAWireless and few other local repairing stores. My question is should I visit? Any idea what this could be and/or how I could fix it?
My device is Samsung Galaxy S8

 

[Rukbat]

The antenna plug probably worked (or got knocked) loose. If this were 2013, it would be a 2 minute fix, but with totally sealed phones it's going to take them longer just to get the phone open. But if that's what happened (and over 5 years of repairing cellphones, and 61 years in the electronic communications industry says it is) they shouldn't charge you an exorbitant amount. It's just opening the phone, pushing the connector down, then closing the phone up. You're really paying for the first and third things. (Pushing the connector down is worth a few cents - figuring out a charge for that would be a loss - it's more work figuring it out than pushing the connector down.)

And in the future, be more careful with the phone. The "I dropped it but it seems to still be working" kind of thing can knock a connector completely out. The phone works, but there's no wifi until you're within a few inches of the router.