Does the 2020 Apple M1 MacBook Pro support 2x daisy chained Thunderbolt Displays?
No, you get only one external display - for two supported displays total and they do not chain (in the case of the mini and two external displays).
One is the MacBook Pro / Air screen and the second can be as large as the 6K Pro Display XDR. The Mac mini has the same limitation - two displays only, no chaining of displays. Initial reports from the Thunderbolt 2 to 3 adapter are very encouraging that those displays work well. As do the latest displays with newer connections.

https://www.apple.com/pro-display-xdr/specs/

Now, just because Apple doesn’t support it, you can add all sort of Thunderbolt docks and USB to HDMI adapters.
Five displays works with third party software + hardware.

https://www.youtube.com/watch?v=Kq_FyjcAULA

This team has tested 5 displays from an Air and 6 from the Mini. It looks like you can push things far more using DisplayLink software instead of the supported direct connection with reasonably priced adapters if you really need more pixels.