Ticks and mites are actually

Ticks and mites are members of the class Arachnida, placed in the subclass Acari. Textbook material lists ticks and mites among common arachnids and notes key arachnid characters — absence of antennae, two body regions, and four pairs of legs — which distinguish them from insects [1]. Scientific overviews identify Acari explicitly as a taxon of arachnids that contains mites and ticks and emphasize their distinction from insects (which have antennae and three body regions) [2]. Additional taxonomic summaries likewise place mites and ticks in the subclass Acari within Arachnida, confirming their arachnid identity rather than classification as crustaceans, insects, or myriapods [3].

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 9: Indian Biodiversity Diverse Landscape > Arachnids > p. 156
2. [2] https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/acari
3. [3] https://winvertebrates.uwsp.edu/Arachnida.html