Creating own VPN-server for external users

Question

I'm trying to set up a VPN-server from my home router so that external users (from other countries) could connect to it. Basically, I want it to work this way:

External User (IP-address "A") -> connect to my home VPN-server (IP-address "B") -> search web with IP-address "B".

I've watched many YT-guides, which I followed thoroughly and step by step, but I'm not sure it works, since another device's IP-address doesn't change.

I've done so far:

• set up a DDNS adderss;
• set up an OpenVPN server in my router settings;
• exported a config and uploaded it into OpenVPN GUI;
• after some googling added redirect-gateway def1 / push "redirect-gateway def1". Unfortunately, none of these have worked so far.

Some sources say I need a statip IP address to make it work.

Any advice on this issue? And more importantly, is the info about a static IP correct?

UPDATE:

1. Somehow I managed to make it work on both Android and iOS devices. IP-address changes to the one provided in the config file.
2. However, the same config (or its copy) doesn't work on any PC (have tried on windows and macos so far). 2a. When I use the same config I get the following error:

    Options error: unknown --redirect-gateway flag: ipv4 

   When I fix it, another error occurs: 2b.

   OPTIONS ERROR: failed to negotiate cipher with server. Configure --data-ciphers-fallback if you want to connect to this server.
   2023-09-02 17:08:18 ERROR: Failed to apply push options
   2023-09-02 17:08:18 Failed to open tun/tap interface
   

   2c. When I add

    data-ciphers-fallback "AES-256-GCM:AES-128-GCM:CHACHA20-POLY1305" 

   I manage to connect, however the Internet is not accessible and VPN keeps reconnecting all the time.

This is config through which I connect on mobile devices:

 client
dev tun
proto tcp
float
nobind
tls-client
remote-cert-tls server
cipher AES-128-CBC
comp-lzo adaptive
resolv-retry infinite
persist-key
persist-tun
remote username.tplinkdns.com port
redirect-gateway def1 ipv4
register-dns

Config I try to use on Windows:

client
dev tun
proto tcp
float
nobind
tls-client
remote-cert-tls server
data-ciphers-fallback "AES-256-GCM:AES-128-GCM:CHACHA20-POLY1305"
comp-lzo adaptive
resolv-retry infinite
persist-key
persist-tun
remote username.tplinkdns.com port
redirect-gateway def1
register-dns

UPDATE 2: Client config:

client
dev tun
proto tcp
float
nobind
cipher AES-128-CBC
comp-lzo adaptive
resolv-retry infinite
persist-key
persist-tun
remote username.tplinkdns.com port
redirect-gateway def1

Server config:

client
dev tun
proto tcp
float
nobind
cipher AES-128-CBC
comp-lzo adaptive
resolv-retry infinite
persist-key
persist-tun
remote *inner IP-address starting with 10.* the same port