I was trying to climb to FL380 in a 737-800 and I noticed that as I got past ~FL250, the aircraft started losing airspeed. I decreased the VS so the speed can stay stable so I wouldn’t stall. Eventually, I did climb up to FL380 but I had to put full thrust on to reach my cruise speed of M.80. Any tips on what I should do next time? I want to make the climb as realistic as possible.
Keep in mind, I had normal weight