I would first make sure the Trackpad cable is fully seated into the logic board, maybe it got bumped during SSD replacement and got knocked loose. If that doesn’t work you can try adjusting the trackpad tension screw and see if that helps. You’ll need a T6 to do this. Make a half a turn, place laptop in upright position and then test the trackpad. If it’s not clicking properly make another half turn and test it again. If you over tighten this screw you can break the trackpad so be careful.
Does the LED on the Power Adapter turn orange or green? What does your wattage show under System Report? Is it just empty? System Report will also tell you if the battery is charging? What does that say? If you click on the battery icon in the Menu bar up top what does it say?Does it show a battery service error or anything?
What if you Option boot and try to Reinstall the OS. Disk Utility is seeing Macintosh HD so something is there. I would try reinstalling the OS and see what that does. How to Reinstall macOS on an M1 MacBook Air, M1 MacBook Pro, and M1 Mac Mini
What about LED 4? Is it on? I would think if LED 4 isn’t lit up then your LCD Panel isn’t being recognized. Is the PRAM reset actually working, you hear it chime multiple times? Do you have an external monitor to plug up and see if you can get external video? I would pull power and try reseating the display cables. It’s worth a try. Meaning of Diagnostic LEDs: 1st LED is the indication of a trickle charge. 2nd is an indication of power being received (machine turned on) 3rd indicates the GPU and computer are communicating 4th indicates the computer and LCD panel are communicating.
Did you follow the step below after putting it back together? These laptops are particular when you pull the boards out and put them back in. To avoid logic board damage, when your MacBook repair is complete but before powering it on, connect it to low-voltage power using a 5-Watt iPhone charger and a USB-C to USB-A cable. These accessories are not included with your MacBook, so make sure you have them ready before you begin
That’s wild how that happened. Was it on a hard/level surface when you were on it or on your laptop? I would try a SMC reset again being sure to count just right when performing the reset procedure. It’s very specific with how long you hold the buttons down in order to get a successful reset. Go here to read up on the SMC reset procedure. https://osxdaily.com/2019/01/14/how-reset-smc-macbook-air-pro-2018-later/
Just wanted to clarify, do the fans kick on high at the Login Window or only once you get logged in and get to your Desktop? What if you Option boot to EFI and let it sit there, do the fans kick on high then?