looking for help via Teamvierwer with TRACCAR (traccar.org GPS-Tracking-Platform)

I am looking for a freelancer who knows the project TRACCAR ([login to view URL] GPS-Tracking-Platform)) very well. I have a droplet at Digitalocean (Ubuntu 16.04.5) with Traccar Server installed and working. I would like to book (for the beginning) a freelancer for 1 hour, who connects to my computer via teamviewer and who I can ask all my questions and who helps me via Teamviewer to implement them: a.) Should I leave it at the JAVA database or is it better to switch to SQL or another database? And how does that work? b.) Is my Ubunto-Droplet at Digitalocean as secure as it is at the moment or can it be secured even better? c.) Is it possible to install Letsencrypt although no Apache and no Nginx are running on the Droplet but only Java? d.) Can I change the icon of the displayed vehicles and how can I do that? e.) Can I also use Google Maps or is it better to stay with Open Streep Map?