Network and printing failure - probably due to broken links <SOLVED>

[Planemaker]

Hello all.
The problem started a while ago with my wired network VPN connections failing regularly. (I don’t use WiFi). The direct network connection is fine but the VPN connections buffer and drop out frequently when streaming TV etc. I’ve since created two l2tp VPN connections which generally work better but not always. I’ve recently had printing problems also. “New” documents generally print OK but “old” documents don’t. I’m using Libreoffice. Version: 6.0.7.3 Build ID: 1:6.0.7-0ubuntu0.18.04.10 CPU threads: 4; OS: Linux 5.4; UI render: default; VCL: gtk3; Locale: en-US (en_US.UTF-8); Calc: CL
My laser printer is a Brother HL-L2300D, using brlaser v4 and my system is Linux Mint 19.3 Cinnamon 4.4.8 kernel 5.4.0-70-generic 64-bit
Device-1: Intel Ethernet I219-V vendor: Micro-Star MSI driver: e1000e v: 3.2.6-k
Local Storage: total: 2.35 TiB used: 735.10 GiB (30.5%)
ID-1: /dev/nvme0n1 vendor: Samsung model: SSD 970 EVO 500GB size: 465.76 GiB
speed: 31.6 Gb/s lanes: 4 serial: <filter>

One thread that I found proposed that the headers of the old documents could be corrupt but digging into my system I think I’ve found the culprit. However, I don’t know how to resolve this.
I have 79 broken links in run/systemd/units. For reasons of space I’ll just give a few examples but all of the failed links are 32 bytes each and there are different addresses for each.
The filenames include these: invocation:cups.service, invocation:systemd-sysctl.service, invocation:dnsmasq.service, invocation:apparmor.service, invocation:ModemManager.service, etc. but as I mentioned earlier there are 79 in total.
I think I’m the source of the problem initially. With all of the networking issues that I had, I tried to uninstall the VPN app. I couldn’t find a method that worked for me (trying cmd and GUI) and so I deleted the files manually. I strongly suspect that I’ve removed an operating file somewhere causing the problem that I have now. I’m not a newbie but I do lack experience and I’m obviously learning as I go. However, this issue has me beaten. I just don’t have enough knowledge to resolve this and I’m concerned that I might make matters worse. Consequently, if anyone can direct me towards a solution I’d be very grateful indeed.
Thanks in anticipation.

[mikeflan]

My thinking is that those are not a problem for you or me:
http://www.mflan.com/temp/broke.png
My internet drops sometimes when I stream, but it usually reconnects in time and does not affect the stream.
I also work on a wired network and the network is fairly reliable (LM 19.3).

[Planemaker]

Thank you mikeflan. I'll leave the broken links alone and will look elsewhere to try and resolve the erratic printing and network problem.
Your help is much appreciated.
Have a nice day.