Well like you said, Sea of Thieves but also Halo does get a fair ammount of active users every month, both infinite and MCC.Which games are "fairly popular"? Halo Infinite? That game is dead. Forza Horizon 5 does "okay" player numbers, nothing major. Grounded's player counts are just like the game's title.
The only XGS live-service game that does consistently decently well IS Sea of Thieves; the other good performers like ESO were already on PlayStation prior to an acquisition.
But then again these games are old news for xbox folk. dude there is no reason for me to get an xbox but if these games came to playstation I would play them, and so would a lot of people. I'm not saying that xbox would outsell sony in their own platform, what I am saying is that there are games of fairly good quality stranded on a shit box.