Three beeps indicate a "base memory read/write test error". Check out "beep codes" for more information.
https://en.wikipedia.org/wiki/Power-on_self-test#POST_beep_codes_on_CompTIA_A.2B_certification_exam Reseating the RAM is the best course of action to remediate the issue of three consecutive beeps during boot, as it may indicate a RAM failure or loose connection. By reseating the RAM, the technician can ensure that the connection is secure and the computer should boot normally. References: CompTIA A+ Certification Exam Objectives 1001, 1.9

The appropriate connection types for connecting an external keyboard to an Android tablet are USB-C and Bluetooth123.

802.11 ax is a wireless networking protocol that utilizes the 5.0GHz frequency and has the best speed and reception among the options given. 802.11 ax offers higher data rates, lower latency, increased capacity, and improved power efficiency than previous protocols. It is also known as Wi-Fi 6 or High Efficiency Wireless (HEW). 802.11a also uses the 5.0GHz frequency, but it is an older protocol that has lower speed and reception than 802.11 ax. 802.11b/g/n use the 2.4GHz frequency, which is more crowded and prone to interference than the 5.0GHz frequency. 802.11n can use both frequencies, but it is also slower and less efficient than 802.11 ax. Reference: https://www.comptia.org/training/books/a-core-1-220-1101-study-guide (page 82)

Opening multiple large Excel files simultaneously requires a large amount of RAM. Upgrading the RAM in the workstation should improve performance. References: CompTIA A+ Certification Exam Guide, Ninth Edition, Chapter 9

Port flapping, also known as link flapping, is a network issue that causes a switch port's state to fluctuate between up and down within short periods of time. This instability affects network connectivity and performance. Port flapping can be caused by various factors, such as faulty cables, hardware issues, configuration issues, or other network issues12. In this scenario, the user's desktop computer is connected via an Ethernet cable and often drops the connection, while no other network users on the same floor are reporting issues. The administrator verified that all authentication systems are working as intended and the Ethernet cable was replaced. Therefore, the most likely cause of the issue is port flapping on the switch port that connects to the user's computer.
References
1: Port flapping - Definition, common causes, and troubleshoot ...
2: Solved: Port Flapping Issue - Cisco Community