Yesterday's post got 850 views, today's — 420. It seems the channel has dropped sharply. But yesterday's publication has already been live for a day, while today's has been up for four hours. For now, this is a comparison of two different conditions.
Below is a checking procedure that helps separate an ordinary discrepancy from a content problem. The numbers in the examples are conditional: they show a way of reasoning, not a norm for Telegram.

Put together a small table
Choose the last ten regular publications. Mark advertising messages and urgent announcements separately. For each row, save the topic, the date and time of publication, views after 24 hours, the number of subscribers at that moment, clicks on the main link, and notable external events.
If there is no data for the first day, start collecting it from the next post. Do not reconstruct past values from memory. Record the time the readings were taken separately: "Tuesday morning" is not precise enough if the publications went out at different times.
Access to extended statistics is determined by Telegram for a specific channel. If you do not have the relevant section, a manual log still allows you to compare the main metrics. Telegram documentation on the availability of statistics.
Check where the extra view could have come from
Telegram has an approximate counter that includes views of forwarded copies. It does not show the exact number of unique readers of the channel. Telegram FAQ.
Next to a successful post, add notes: it was forwarded to another channel, a partner linked to it, it was part of an ad, it was added to the pinned post. A one-time spike after such an event should not be turned into a new mandatory minimum for every publication.
Account separately for ordered views. If only some of the messages had them, the final counters cannot be compared as the pure result of editorial work. Save the order date and the affected links; for a content test, choose publications with comparable conditions.
Separate the question of delivery from the question of usefulness
A low number of views and a lack of inquiries require different checks. In the first case, look at the age of the publication, the frequency of neighboring messages, and external sources. In the second, walk the reader's path: is the topic clear, is the link visible, does the right page open, does the offer match the expectation.
A conditional example: two posts about bicycle repair have similar views. One offers to "learn more," the other leads to a booking with a clear list of services. The difference in inquiries may be related to this step. To test the assumption, keep the topic and format the same, and in the next comparison change only the call to book.
Run one careful test
Do not change the time, length, illustration, and topic at the same time. Otherwise, even a successful result will not tell you what to repeat.
Choose two comparable categories or a recurring format. For example, publish breakdowns of the same complexity and test two versions of the first paragraph. Compare several publications in the same window, not two random posts. With a small number of publications, the result remains an observation, not a proven rule.
Write down the decision in advance: "If people open the link but do not submit the form, we check the form; if they do not open it, we look at whether the offer matches the topic." This keeps you from uselessly changing the entire design after every weak post.
For a separate task with a chosen publication, you can review the terms for views. Account for such orders separately from organic reading. An increased counter by itself will not explain why the audience liked the topic, and will not replace clicks or inquiries.