An indie app I’ve been using lately and recommend: everyday.app.
It’s a “just enough” (read: minimalist without being pretentious) daily habit tracker. Its power comes from its simplicity.
I suggest starting with two habits: “Do 1 pushup” and “Do 10 pushups”. Don’t allow yourself to add any new habits until you’ve done those for 4 days. On day 5 you can add another two more: “Floss 1 tooth” and “Floss 10 teeth”. Four more successful days of all four habits. Then two new habits. And so on.
$12 a year is an absolute deal.