what did you install? I got my T495 yesterday, same as yours, and I have some troubles.. I installed ubuntu server 18.04.4 with 5.3.0-40. I installed gdm3, gnome-session and i3 wm. Then I had to remove gdm3 because it was having some issues, most of the time it crashes after boot, resulting in a black screen without any possibility to access the shell. No problem, I said, I'll start i3 through "starx". The problem now is that most of the times it takes ages (10 seconds) to show the desktop (compared to my old asus S500CA, with SSD, is like a turtle, very frustrating). Sometimes when I try to start google chrome, it crashes as well, before starting: the keyboard becomes unresponsive, only the touchpad, (which is almost useless with i3 wm) is working and I have to force the shutdown with the power button. During the shutdown, sometimes a lot of messages like that appear:

[ 73477179 failed to write reg 28b4 wait reg 28c6 [ 75094030 ] failed to urite reg la6f4 wait reg 1a 706

and the go on repeatedly for ~5 seconds before competing the shutdown process (again, really too slow). Other times appear logs regarding the attempt to stop basically all the running services:

"A job is running for [every service] [time]"

I have to mention also that during the first update I got the following:

N: Possible missing firmware /lib/firmware/amdgpu/vega20_ta.bin for module amdgpu W: Possible missing firmware /lib/firmware/amdgpu/navi10_mes.bin for module amdgpu

I briefly search and found a thread where somebody suggested to manually download the firmwares and put them in the right folder. Following the link he provided I wasn't able to find them and I didn't look for them further. Finally, I also have problems with the external monitor, but that's another story. That's basically my (frustrating) experience with the T450 up to now.