Hello:
I have two computers with Catalina 10.15.7 and in both it has happened to me that they restart when I log in, it happens to me that there are 2 or 3 restarts and then they already work well, these are the characteristics:
Device 1:
Gigabyte GA-H170-Gaming 3
Intel Core i7 6700
16 GB Ram
RX 570 4Gb
Adata 240Gb SSD
Device 2:
Gigabyte 365 M Aorus Elite
Intel Core i7 9700k
32 Gb Ram
RX 5700 XT 8GB
Adata 240Gb SSD
In both devices, the same thing happens, two or three reboots and it is stable, in both devices I have Windows 10 on an M.2
In device 2, I have two monitors, one for hdmi and the other for displayport, but the one for displayport sometimes behaves strange, so I disconnect it, I don't know if I'm missing any configuration, also the ariplay doesn't work for me it does not display on apple tv.
Best regards
EDIT:
After like 8-9 reboots it already worked
https://photos.app.goo.gl/MvzD5Awm3r5xXbK67