afraid.org DDNS connection to local server is very slow (often timing out). looking for advice/help troubleshooting

Background: my current project is to re-style all the JSPs in a struts 2 web application to modernize the its look. The project team is only a few people, so we largely do our work remotely on local machines and then sync changes manually as we prepare for rollout. I'm on Windows deploying my code to a Tomcat server for testing, and the server pulls its data from an Oracle database running in a Centos VirtualBox.

While using a localhost url was fine for my own testing purposes, I needed a way to connect my teammates to my machine. to do this, I've connected my computer's IP address to a dynamic dns (ddns) service at freedns.afraid.org and set-up forwarding on my router to route port 8080 traffic to my local machine (base URL example: http://nameOfMyApplication.chosenDDNSDomain.com:8080/nameOfApplicationRootDirectory/)

Specs:

• processor: Intel core i7-9700k cpu @ 3.60ghz
• installed ram: 16.0gb (15.7gb usable)
• os: Windows 10 Pro 64-bit version 1903
• internet: wi-fi connection to at&t fiber
• router: Arris bgw210
• server: Apache Tomcat version 6.0.37
• Java runtime environment: 1.6.0_45
• vm: Oracle VirtualBox version 5.2.6 r120293 (Qt5.6.2)
• vm os: Centos version 5.7
• database: Oracle database version 11.2.0

Problem: while I think this configuration should generally work for very small load testing (3 users maximum), I'm running into issues even when I am the only user testing the application. Pages take a long time to load, and the connection times out roughly half the time on my local machine. My teammates have had timeout issues in the past as well, but I'm unsure if their load times are usually as bad as mine are "locally" (connecting to my own machine through the internet) since they haven't done more than 2-3 testing sessions. our website build involves a "baseUrl" string, so I don't believe I can have the application built for both localhost and ddns access at the same time. I've tried the issue online, but it's hard to find answers specific to this strange ddns/Tomcat/virtualbox setup I'm using. I think it's really an option to change this setup, as I would need to convince my teammates to change the way they've been doing things for over a decade.

Questions/requests for advice:

• would it be possible to have a struts 2 application accessible through both localhost and ddns look-up? because the website builds all URLs using the baseUrl string, my initial thought is that this can't be done, but if the issue is caused by me accessing my own machine through ddns, maybe there could be some way for my teammates to use ddns and me to use localhost?
• is there anything about connecting to my own machine through the internet that would make things load especially slowly? While I expect some slowdown since my machine is sending the request, receiving/processing the request, responding to the request, and receiving/processing the response, I'm wondering if I should expect the slowdown to be so great that the site is not reliably usable.
• how would I go about determining where the slowdown is occurring? while the domain I'm using for my ddns has been running without any apparent downtime, I'm wondering if there is some domain-specific issue or maybe an inefficiency in how freedns.afraid.org domains do dns look-up. essentially, I'm looking to find out if my problem is caused by the general strategy I'm using or just the specific ddns provider I chose.