Everyone should work on what works best for oneself. Each step one makes in the direction of being a G-d fearing Jew is considered beautiful to G-d. Some will choose to be extra careful with halachos like shmiras halashon and the like. Others will choose do be machmir with something like chalav stam.
It’s unfortunate that you find people trash talking others during the aseres yemai teshuva but it’s also unfortunate that you choose to judge them during the aseres yemai teshuva. If the lack of yiras shamayim in a another yid gives you so much pain, use the chance to be mekarev them by gently reminding them of the seriousness of the time.