The most likely solution to this issue is to enable cellular data. After a business trip, the user may have disabled cellular data to avoid roaming charges, or the phone may have been set to Wi-Fi only for internet access. Enabling cellular data would restore internet access outside of Wi-Fi networks.
Reference: CompTIA A+ 220-1101 Exam Objectives, Domain 1.4 Mobile Devices - Wireless/Cellular Network

The Network and Sharing Center is a Control Panel utility that allows users to view and modify network settings, such as IP address, subnet mask, default gateway, DNS servers, and network profiles. To change the IP and gateway settings of a Windows workstation, the technician can follow these steps:
* Open the Network and Sharing Center by clicking on the network icon in the system tray or by searching for it in the Start menu.
* Click on Change adapter settings on the left sidebar.
* Right-click on the network adapter that is connected to the network and select Properties.
* Double-click on Internet Protocol Version 4 (TCP/IPv4) or Internet Protocol Version 6 (TCP/IPv6) depending on the network protocol used.
* Select Use the following IP address and enter the desired IP address, subnet mask, and default gateway for the workstation. Alternatively, select Obtain an IP address automatically if the network uses DHCP to assign IP addresses dynamically.
* Click OK to save the changes and close the dialog boxes.
References:
* The Official CompTIA A+ Core 2 Study Guide (220-1102), page 2171
* How to change the IP address in Windows 10 and Windows 11 (4 ways), section 12

Removing the user-installed antivirus software program is the best way to resolve the issue of extremely slow performance caused by installing additional real-time protection antivirus software on a PC. Having more than one antivirus software program running at the same time can cause conflicts, resource consumption and performance degradation. Uninstalling one antivirus software program and installing a different one, activating real-time protection on both antivirus software programs, enabling the quarantine feature on both antivirus software programs and launching Windows Update are not effective ways to resolve the issue.
Verified References: https://www.comptia.org/blog/why-you-shouldnt-run-multiple-antivirus-programs-at-the- same-time https://www.comptia.org/certifications/a

In Windows 10, there are privacy settings that control access to certain devices, such as microphones, cameras, and other input devices. If the microphone is not enabled under these privacy settings, the VoIP application may not have access to it, causing a lack of outgoing audio.
The technician can go to the Windows 10 Settings menu, select the Privacy submenu, and under App permissions, select Microphone. The technician should then turn on the toggle switch for the VoIP application to allow it to access the microphone.
Removing the microphone from the USB hub and plugging it directly into a USB port on the PC may or may not solve the issue, as the issue could be related to the privacy settings. Deleting the microphone from Device Manager and scanning for new hardware may also not solve the issue, as the issue could be related to the privacy settings. Replacing the USB microphone with one that uses a traditional 3.5mm plug is not recommended, as it would require purchasing a new microphone and may not solve the issue.

devmgmt.msc is the MMC snap-in that opens the Device Manager, a tool that allows the technician to view and manage the hardware devices and their drivers on the computer1. If the applications are not updating properly, it could be due to outdated, corrupted, or incompatible drivers that prevent the hardware from functioning normally. The technician can use the Device Manager to update, uninstall, rollback, or disable the drivers, as well as scan for hardware changes, troubleshoot problems, and view device properties2.
gpedit.msc is the MMC snap-in that opens the Group Policy Editor, a tool that allows the technician to configure the local or domain group policy settings for the computer or a group of computers3. Group policy settings can affect the security, performance, and functionality of the system, but they are not directly related to the application updates or the hardware drivers.
perfmon.msc is the MMC snap-in that opens the Performance Monitor, a tool that allows the technician to monitor and analyze the performance of the system and its components, such as processor, memory, disk, network, etc4. Performance Monitor can display real-time data or collect log data for later analysis, as well as generate reports and alerts based on the performance counters5. Performance Monitor can help the technician identify and diagnose performance issues, but it does not provide a way to manage the hardware drivers.
References:
* The Official CompTIA A+ Core 2 Study Guide6, page 223, 225, 227, 228.