I am using the python-telegram-bot library in a bot that posts a summary of everything uploaded to a channel in a 24h period and it updates itself afterwards with any new content. It's currently being used by about 250 pretty active channels, so I would prefer avoid using the copy_message and forward_message methods. Is there any built-in or at least simpler way of achieving the same result? Thanks in advance!
No, there is not. Note that this is not a limitation of python-telegram-bot, but of the Bot API. See this FAQ entry of python-telegram-bot and also this GitHub thread on the repository of the Bot API itself.