DNS propagation does not exist, it is incorrect terminology as DNS is not top down, but just governed by caches renewing their entries based on TTLs on records (and other more complicated rules, like DNSSEC RRSIG expirations, DNS Negative TTL, etc.)
In theory the TTL gives the maximum amount of time a cache can keep the entry.
So a cache is theoretically free to do things before it, hence kind of lowering it.
In theory again, a cache should honor it and not increase it.
In practice it is known that some caches override the value, especially if too small. Various nameservers software have configuration option to do so.
While I do not know a definitive study on the subject, my ballpark recommendation is to stay way from TTL lowers than 5 minutes because otherwise you have a risk of some caches not honoring it. Others sources are more optimistic than me and says anything above 30 (seconds) is fine. YMMV.
There is at least this study, using RIPE probes, from 2017:
It repeats the same sentiment: "It is publicly known that some cloud providers and CDNs override the original values provided by authoritative servers within their networks." based on this result in the study: "We have seen in Table 2 that 4.17% of the resolvers will actually increase the TTL value of our RRs in this measurement."
For further debug you will need to give more details on the specific caches where you see a behavior contradictory to your TTL configuration and you (and/or your clients) might want to try contacting their administrator to see if their rules can be changed (very low probability for that to succeed, but if you do not even try to contact them, absolute zero probability that things will change).