I have the same problem and have posted here
Creating a template (legacy) doesn't appear to work even though it matches. Need to read up on datastream
[2022-01-22T15:30:10,295][WARN ][o.e.c.m.MetadataIndexTemplateService] [elastic] legacy template [.logs-deprecation.elasticsearch-default] has index patterns [.logs-deprecation.elasticsearch-default-*] matching patterns from existing composable templates [.deprecation-indexing-template] with patterns (.deprecation-indexing-template => [.logs-deprecation.*]); this template [.logs-deprecation.elasticsearch-default] may be ignored in favor of a composable template at index creation time
[2022-01-22T15:30:10,296][INFO ][o.e.c.m.MetadataIndexTemplateService] [`Preformatted text`elastic] adding template [.logs-deprecation.elasticsearch-default] for index patterns [.logs-deprecation.elasticsearch-default-*]