So, I have this tablet, it's running Android 9, and there are no options anywhere in the OS to check for updates and install them the way I would expect there to be. Last update was 2020, and I can see there have been updates for this device since. 

I can usually work this stuff out for myself, but I am a bit perplexed. I could probably download and install a firmware from sammobile.com or something, but I can't recall which sites are safe any more since it's been a long long time since I had to do a manual update. 

TIA