How to implement secure access to Apache/Mysql server?

Question

Apache HTTP Server

We have:

• local server
• LAN computers
• Remote laptops with mobile Internet (USB modems), we can configure them as you like
• Web application (processed by Apache on the server)

Necessary:

• Maintain server access security
• Open access to the server to remote laptops via mobile Internet

My options:

1. I thought about restricting access by IP, but when accessing from the mobile Internet, IP is dynamic
2. Use Dynamic DNS for laptops or raise your own server
3. Set up a proxy server on the local network

Advise how best to solve the problem of access and do it safely enough? I repeat: access is required through the browser.
AP1: Requires access without additional programs. For a laptop user to open a browser, enter a username and password, and be able to use the system.

Answer 1

The task was solved by installing the ssl certificate and basic authorization.

Answer 2

https
secret page - domen.ru/asdcf0000lalala
phpmyadmin
basic autorization
monitor access logs if you are afraid of brute force.
Add an ip limit to the range of your mobile and office subnets.

Answer 3

The first thing that comes to mind is a VPN, it will solve all your problems.

Answer 4

Put secure user logins and passwords on the web application and make sure that access to any parts of the application is impossible without a login and password. (Most applications are protected in this way)
Allow access for the entire possible range of IP addresses allocated by the provider, forbid other addresses. (I think you can find out the ranges. And if necessary, you will supplement it)
Use https. (If you are afraid of "wiretapping")
Another option is to disable access to the application from the Internet. Access to do only from the local network. And let it into the local network from the outside through VPN. Then the security lies with the VPN.
Make one-time passwords via SMS.
Sign your computers of your users with a digital key.