Extremely suspicious. Also, discussing about cheating isn’t allowed in public forums. Better to do it in cheating forum club: https://www.chess.com/club/cheating-forum
FYI Accurate moves are only difficult to find if you pose problems that are to complex for your opponent. If you play an openening both are familiar with and then you hang your pieces each turn afterwards it might be possible for your oponent to get over 90 percent accuracy just because taking the hanging piece is the best move and is super obvious. Accuracy by itself isnt a guarentee of anything bad, context is always king.
https://support.chess.com/article/209-how-do-i-report-someone
Anyone suspicious you can also report. As advised above cheating forum is best place for this discussion also.
Thanks
Its not making a fun place for a beginner. People with suspect accuracy. Then there's the other issue of playing people with a daily rating 400 or so but their rapid rating is 1000 plus.. Surely if you can play well with stricter time control you can play just as well with longer to think. Probably will stick to playing real life friends and over the board going forward.
Would it be suspicious for a player of my level of below 400 to be 99.7% accurate over 20 moves.
I play a work friend often with a higher rating , 7something and although he routinely kicks my behind he’s never accurate to this level.