I couldn’t say without knowing what data sheet you looked up but OTOH, I was going off memory for the 4056. Given some of the moving choices that Heltec makes, YMMV if you read it can cope with more as you’d need to be sure it’s got the part you are expecting on the module.
Plus you are going to dumping a fair amount of energy with 24V in to a max 4.2V battery and as the battery is a LiPo, there is potential for the potential difference to become energetic and make a permanent difference.
TL;DR: 6V solar panel in to a V3 outside in the garden I’m OK with. Handheld device charged via USB, adults only.