How to combine two Internet channels (one provider) into one to increase speed?

Question

System administration

Good day, dear administration gurus!
I have a problem with the provider.
Opened an Internet club from a small one.
In my city, the provider issues a maximum of 4 Mbps per wire at a rate.
No matter how much they beg to give more, they cannot give for their own reasons.
Than to put on each wire on the router, I thought it might be possible to combine two channels into one, to increase the speed.
Question: How can I solve this situation, given my noobness in Linuxoids.
If possible, please give detailed information with step-by-step actions.
Thanks in advance, dear connoisseurs!

Answer 1

Combining the bandwidth of two Internet channels and simple fault tolerance

Answer 2

also look at microtik, there you can also combine a lot of things, but the setup is a little more complicated

Answer 3

pfSense