That will differ between different speakers and will change in time, decade to decade. And now, that "my přítel" in singular means more and more exclusively just "my boyfriend" in many contexts, it is changing even more. You can treat it as a synonym for practical purposes.

There are some nuances, a group of children is more likely "kamarádi", but "přátelé" is also possible.

If anything, then "přátelé" might be better in formal situations. In some situations "kamarádi" might be too much evoking a group you go to pub with or a group of children. And if you want to demonstrate strong affection to a dear friend, "přítel" is probably better.

But as I said already, "přítel" also tends to mean "boyfriend" more and more, so to avoid that meaning many might use just "kamarád". Especially in singular.

But it is better to look into a good dictionary and corpus to see all situations and examples. http://bara.ujc.cas.cz/psjc/search.php?hledej=Hledej&heslo=p%C5%99%C3%ADtel&where=hesla&zobraz_ps=ps&zobraz_cards=cards&pocet_karet=3&ps_heslo=p%C5%99%C3%A1tel%C3%A9&ps_startfrom=0&ps_numcards=0&numcchange=no&not_initial=1 http://bara.ujc.cas.cz/psjc/search.php?hledej=Hledej&heslo=kamar%C3%A1d&where=hesla&zobraz_ps=ps&zobraz_cards=cards&pocet_karet=3&ps_heslo=p%C5%99%C3%ADtel&ps_startfrom=0&ps_numcards=523&numcchange=no&not_initial=1 https://kontext.korpus.cz/view?ctxattrs=word&attr_vmode=visible&pagesize=40&refs=%3Ddoc.title&q=~gNdYNY7nRw&viewmode=kwic&attrs=word&corpname=syn2015&attr_allpos=kw https://kontext.korpus.cz/view?ctxattrs=word&attr_vmode=visible&pagesize=40&refs=%3Ddoc.title&q=~oGZiWIIP4E&viewmode=kwic&attrs=word&corpname=syn2015&attr_allpos=kw

I will allow this.