Russian distinguishes between true comparatives with по- (attenuative forms) and positive forms disguised as comparatives.
Овощей нужно есть побольше обычного // You should be eating a bit more vegetables than you usually do.
Эта штука посильнее, чем "Фауст" Гёте. Любовь побеждает смерть. // This piece must be more intense than Goethe's "Faust". Love triumphs over death.
Here, the comparative adjectives are attenuatives, which would be have been similar to English forms with "-ish", like "red / reddish" etc., if those worked with comparative forms.
It sounds really weird with used with намного ("much") but works perfectly with немного ("a little"), just the same way "it's very bluish" is weird but "it's a little bluish" is OK in English.
So it's not always "a little", it could just as well mean "seems like", "to some extent", "kinda" etc., when you doubt the degree or validity of the comparison or that you're applying the right adjective at all.
Тебе нужно есть овощи, да побольше // You should eat vegetables, lots of them, too.
Возьми бинокль посильнее, Иван, и проводи меня наверх. // Ivan, take binoculars, the powerful ones, too, and walk me upstairs.
The comparative adjectives here are in fact positive forms, with emphasis on the property mentioned ("really a lot", "really powerful" etc.)