I am at day 10 of a new sourdough starter. I started using rye flour and all purpose flour but due to the COVID 19 pandemic I had to eventually only use rye flour because it is what was available. The starter isn't rising as much as I would expect.. usually it rises 1 or 2 centimeters, but it does bubble and seem active. When I start mixing it before feeding it seems like it smells like eggs. I feed it every 12 hours and keep it in a warm part of our home. I am not sure if I should start over (finally found unbleached all purpose flour!!) with an all purpose flour and rye flour mixture or if I should keep going.   Sourdough experts- please help!!! 
Typically you can begin to give up at around day 5-7. (Especially if you've taken an aggressive feeding schedule.)  With an aggressive feeding schedule (2-3 times daily), you should begin to see bubbling and sour notes by day three (and is a good indicator for collecting the Lactobacillus bacteria).  Ref: Full Proof Baking  By Day 5, I typically give up if there's no rise or sour notes.  There's two common factors that make sourdough fermentation difficult.   the Type of flour      If you use plain/white, there's not enough nutrients - so adding rye, ground cereal, or anything with whole grains will help.  The water quality      Chlorine or other chemicals might be present in your source, so getting a tap filter and boiling/resting the water will assist.    Summary: - try increasing the feeding cycles until you get the sour notes, keep note of the water/flour until you get some smell/reaction. 