I have multiple subdomains. Do I need to verify each subdomain with a separate TXT record pointing to gscjn4fuas4dr27sjp0uf7e266jmg3ge.site?

Generally, you only need to verify the root domain. Once the root domain is verified, Google automatically includes all subdomains. However, if you want to specifically manage and analyze data for individual subdomains within Search Console, you may need to add them as separate properties and verify them individually. Check Google's documentation for the most up-to-date guidance.