Can anyone recommend a router that will give a 1200 transmit rate for 14" MacBook Pro w M1

To produce that 1200M bits/sec maximum data rate, you would need a Router that supports 802.11ax (Wi-Fi-6) and uses the 5GHz band (typically such devices also support a 2.4GHz band as well, but that would only provide at most 195M bits/sec maximum theoretical speed).

Whether that number is actually attainable depends on the distance from Router to Mac, density of any wall and other building materials, and the conditions in your "network neighborhood". If you live in apartment building, with many other Routers in range, that 1200 number is likely to be impossible over Wi-Fi.

If you can connect with an Ethernet cable (and dongle if required), Gigabit speeds are ordinary, and 2.5G speeds are readily available. 5.0G and 10G speeds are possible.

Wi-Fi 6 802.11ax is somewhat faster for a single connections than is Wi-Fi 5 802.11ac.

In a good Wi-Fi network environment, you’ll probably get most of a gigabit (say, ~700 or ~800 Mbps) with Wi-Fi 6, per channel.

Wi-Fi 6 is way better in crowded environments, with more stations, with lower latency, and better security.

If 1.2 Gbps is minimally needed per station, expect to install 2.5 GbE or faster wired, or optical networking.

I like Linksys MU-MIMO routers: https://www.amazon.com/Linksys-MR9600-Dual-Band-Wireless-Future-Proof/dp/B0897ZSSQF/ref=sr_1_4?crid=2X1LMYFOZ656&keywords=linksys+ea9500+max-stream+ac5400&qid=1666209037&qu=eyJxc2MiOiIxLjQxIiwicXNhIjoiMC45NyIsInFzcCI6IjAuMDAifQ%3D%3D&sprefix=Linksys+EA9500+Max-Stream+AC5400%2Caps%2C78&sr=8-4

<< Wi-Fi 6 is way better in crowded environments ... >>

Quite right if the crowd is US, i.e., you are supporting a whole lot of your own stations.

When the crowd is THEM, (your Neighbors' Routers) you can't always use 80MHz channel successfully, and your neighbors' data tends to clobber your data, so everything can slow way down.