TRACCAR specialist wanted (Project traccar.org, java )

I am looking for a specialist for TRACCAR ([login to view URL] Project, java) who is able to connect to my PC via teamviewer and can answer my questions about TRACCAR and then - if possible - solve them together with me directly on my server.                                              ● This are my questions:    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?