Hi there!
And ofc you can use this thread. And also-10 games is no sample. You can drop 10/15 BIs like nothing. It's hard to do so in HU games, especially in the regular/turbo format. It shouldn't happen often, but it will happen. And it's absolutely possible that loose fish you played against just run hot for 10 games and that's it. It will happen to you as well. Your flush will always complete and he's gonna have a straight or lower flush, you hit full house, he hits trips etc etc.
Vs these type of players-that call a lot preflop and are stationary post-I opt to have a higher limping range(they usually play very straight-forward in limped pots), value bet thin-like 3 barrel second pair, or bet 2 pair on 4 to straight. Or even cbet twice with Ax when you feel he's chasing draws/calling worse. Also-reduce your bluffing range and cbet less on drawy type of boards. F.e. I will still cbet dry boards like A74r or K32ss, or T43. Also-maybe he doesn't fold on 1 bet, but will fold on a second-tripple barrel. Which makes a cbet on 456 type of board very bad, but given the possibilities for you to barrel and him to fold-it becomes great. F.e. a lot of players will play fast their weak top pairs such as 6x on this flop, so if he just c/c, you put him on some draws/mid/third pair and can barrel him off easily on good turn/river run out(overcards).