Where there is mobile internet, where there isn't

Hi
I use FP3 2019 on a daily basis (bought it off the shelf Sept 2020) with great satisfaction.
However, in the last two weeks I noticed that it cannot connect to the ProtonVPN network. Then it worked fine. Then sometimes it wouldn’t even connect to the wifi at home, while my wife’s (also has FP3+) phone would connect to the wifi.
There was one day this week when I got emails, signal messages, other notifications in the early afternoon, that’s when I noticed I hadn’t had mobile net all day.
My guess is that the mobilenet/wifi component is not replaceable in the phone, I guess it is built into the motherboard, so I am in trouble.

Anyone have any ideas? How can I fix it? How do I not have to look for a “new” (i.e. second hand) phone?
I’m waiting for your answer. Thank you.

Update:
This morning, the phone was not connected to the wifi and the mobile internet was not working in our apartment. I went shopping in the morning, and suddenly I was on the street and received all the messages, emails and notifications since the night before. I think this is not good and I would like to repair the phone if possible. Or if that doesn’t work, I’ll have to look for a replacement (by the way, I’m already in the process of buying an FP4 from the Dutch marktplaatz site, luckily I have a friend living there who can arrange this for me, so I might have a second hand FP4 for about 330 euros).

Translated with DeepL.com (free version)

Maybe first try to run the phone some time in safe mode to exclude third party apps?

And what does the status bar show when this happens? If not connected you should see that or not?

Dear yvmuell!

I apologise for the late reply, I have time to write to you now, but I have taken pictures before.
First of all I don’t know what you mean by safe mode? How do I start the phone?

I am currently running a /e/OS 1.8-s-20231207360611-stable-FP3 android version on the phone.
The left phone is my own, the right is my wife’s FP3+ running google android.
Both phones are running proton VPN, which I can see has no data traffic.
I have noticed for about half a year now that it might have slower mobile net than other phones, but I put that down to the VPN.
The pictures were taken on 23 December.


Since then, the thing is that when I turn it on in the morning, I can see if there is mobile net or not by the vpn connection. The phone is connected to the wifi at home, but sometimes it still happens that you can’t see it while the rest of the family is working.
I turn the phone on in the morning, if there is no mobile net, I restart it. Sometimes it works on wifi but mobile net. And there are times that if I turn the wifi off and on, mobile net works.
At the moment I use it so that if the mobile net is on, I don’t turn the phone off, and even then I run into the problem that sometimes it doesn’t work.
It is very annoying as I need mobile net for my work.
As I see you have a similar problem, I found this in a fairphone newsletter:

Precisely because of the above problem, a Dutch friend of mine bought me an FP4 phone for my wife, and I thought of buying his for myself.
I would like your help on this if you can. Parcel shipping to Hungary is very expensive, however if it is possible my friend would send you the phone. I would order a case for the “new” FP4 from the fairphone site, where you could use the coupon code offered to the fairphone angels to send the phone and the case you ordered home in one package.

Do you think this is possible?
Looking forward to your reply, thanks in advance for your help.
By Lajos