Suspect it's a wifi issue too. Some possibilities:
- 2.4 / 5ghz as others have mentioned
- The intel mac may have connected first and is sucking up the bandwidth, and there isn't much left over for the M1 mac. (It's the responsibility of the mesh equipment to sort this out. But some are better at this than others)
- As you have a mesh wifi network, the M1 mac may be connected to a further away access point and not getting as much bandwidth. The M1 macs have a much newer radio system so it might be holding onto a further away access point or working around the intel mac in some way. (Again, some mesh equipment is better at fixing this than others.)
- The M1 mac might be connected to an access point that is re-using its own wifi to connect back to the home gateway, whereas the intel might be connected to a hardwired (ethernet-supplied) access point or the home gateway itself.
- Possible short-falling in your home router itself.
You can test by turning off other computers and streaming with just your M1 mac. Put it near to an access point that is directly wired to your home gateway. Turn the M1's wifi on and off to encourage it to reconnect to the nearest access point. Or even better, connect directly via ethernet and a USB dongle.
I don't know what TP Link stuff you have, but am not a huge fan of it. Amazon's Eero (non-pro) kit is well reviewed (and it's what I have) and is often around half price especially on Black Friday and Prime days.
If the TP link kit is here to stay, then try to have each access point connected via ethernet (or powerline) back to the main router, if it's the type of kit that even has ethernet ports.
Edit: 2.4ghz travels further, but carries less data, and 2.4 ghz radios are not as good at sharing out data between multiple devices, which becomes a problem when your mac can see 5-10 wifi networks from neighbours. 5ghz doesn't travel as far, but carries more data, and Wifi 5 (802.11ac) (only runs on 5ghz) is better at sharing between devices.
Try to make sure all your wifi devices use Wifi 5 (new name for 802.11ac but it's the same thing) and use the 5ghz band. (It's normal to have a few devices that can't, but the less you have on 2.4 ghz, the better)