=> How to combine two wifi networks to get a faster internet

There are 3 main ways of doing this:

1. You can use a router that allows connection load balancing to split your
usage over the 2 (without you having to do anything). Note this way does not increase the speed you'll get on a single threaded download any more than you'd be able to get over either link on it's own; IE: 10Mbps + 10Mbps won't give you a 20Mbps download speed, but if you were downloading a torrent with multiple connections you could see it coming down at 20Mbps.

2. You can use a bonded end-to-end service from your ISP, MLPPP (Multi-link PPP) is one of the most common options for bonding ADSL services, it's quite common for ethernet over copper services to use up to 8 phone lines bonded then presented to you the customer on an ethernet port too.

3. If you have access to a server in a data-center and a MikroTik router you can perform interface bonding using tunnels from your home router to this server.
This for instance could allow you to bond 8 x 20Mbps/2Mbps ADSL services together giving around 140~Mbps/14Mbps after accounting for minor packet loss and overheads involved with using ethernet-over-ip tunnels.

DSL Bonding in action (this setup uses 4 x DSL's on 2 bonding interfaces, doing a bandwidth test you can see I get 72Mbps across 4 x 20Mbps links):

                                                                     Thanks💀