“_M” is the only one that’s bad as far as I can tell.
“AS” bottom-up is probably fine? I don’t know the rules. The words it could turn into by adding “racist” or “rapist” would be valid words, “sac” and “sap”.
_M has a tile above it, meaning this can be anything. There are plenty of words that end in _m.
Scam, scum, slum, plum, trim, tram,
The only bad one is SA
I was going to say that Trump, being a proper name, isn’t a word, but my brain rebooted and I remembered that Trump is absolutely a word.