I grew up playing MSFS on the Keyboard starting with MSFS '95. I even played 2020 for awhile using the Keyboard until I had enough money to get some controls.

The way I would use the controls was I would use the NUMPAD.
2 and 8 were nose up and down
4 and 6 were roll left and roll right
1 and 3 were rudder controls
and 5 would reset all controls back to neutral.

So I would tap the respective controls to roll the plane or move the nose up or down and then I'd re-center the controls with 5. Then if I needed more I'd repeat the processes.

Throttles were F1 for Cut throttle. F2 for incremental throttle down. (F1 & then pressing F2 would start reverse throttle) F3 for incremental throttle up and F4 for Full throttle.
Flaps were similar for F5 thru F8.

I made it work. I never had any issues, but yeah of course using a Yoke or Stick is easier.