wait it's in beta and only have in Google own phones Nexus. you know it will ne stock android when Google release it for public then Developers personalise it with own User interface, then they test bugs in own ui. so it will take time. I think this year end premium phones surely get Android 10 update. one think more that it's not Android Q dear, Now Google named their upcoming android os Android 10 not Q
why not? as you know traditional update policy of every Budget mobiles, You get two major Upgradation of OS. so if Samsung already provides 2 upgrade then you didn't get android 10. example if your phone comes with android 7 nougat then you didn't get it but if your phones come with preloaded Android 8 oreo then you goted 1 upgradation already called Android 9 and you are eligible also for 1 more upgradation that will be android 10. but remember that as I told that is a traditional policy not confirmed.