The bridge works by downloading https://t.me/s/<channel_name>. That page only shows the latest 20 posts in the channel (unless you scroll up, which the bridge can't do), which is why TelegramBridge only returns the latest 20 posts.
To get more then 20 posts we would need to fetch them from elsewhere I think. I'm gonna leave this issue for someone else to implement.

Someone asked me for this, I implemented this for money.
Here is the modified bridge.
https://github.com/em92/rss-bridge/blob/58746t/bridges/TelegramBridge.php

Also that modified bridge somehow solves #1901

Okay cool, so just yeet that into a pull request?

No, I won't accept this feature. Bridge with this feature will generate a lot of traffic to telegram and possibly will lead to ban.

No, I won't accept this feature. Bridge with this feature will generate a lot of traffic to telegram and possibly will lead to ban.

Может добавить его как отдельный бридж? Чтобы каждый мог при необходимости использовать это из коробки (думаю такие запросы будут повторяться тк не все смогут найти этот тикет)
А хостеры публичных бриджей смогут выключать это чтобы не получить бан

The bridge works by downloading https://t.me/s/<channel_name>. That page only shows the latest 20 posts in the channel (unless you scroll up, which the bridge can't do), which is why TelegramBridge only returns the latest 20 posts.
To get more then 20 posts we would need to fetch them from elsewhere I think. I'm gonna leave this issue for someone else to implement.

It doesn't need to scroll up
https://t.me/s/telegram?before=20 and you get first 20 posts, https://t.me/s/telegram?before=40 and you get 21-40 posts, etc
There no too much channels with 1k+ posts
I think it will be cool feature out of the box
But yes, it's probably a headache for public instances, some possible restrictions are needed
@em92 what do you think about that? seems you have another implementation

this is still interesting. those before params still works