How To Edit The Title Tags In Your Shopify Template?

i have tried to replace this in head.liquid:

<title>{{ seo_title }}</title>

with this:

<title>{{ page_title }}{% if current_tags %} – tagged "{{ current_tags | join: ', ' }}"{% endif %}{% if current_page != 1 %} – Page {{ current_page }}{% endif %}{% unless page_title contains shop.name %} – {{ shop.name }}{% endunless %}</title>

but it doesnt work.

I would like to change the structure of the title meta tag for seo including also the tags and the product types of the search function.

for example for this url:

https://seashepherdstore.it/collections/uomo?q=tg_:Black+tp_:felpe

i like this meta tag title:

collection(uomo) + product type(felpe) + tags(black)

yes the code is similar to how I already want it.

I think then that to obtain what I want I can only make ad hoc collections like:
Man-hoodie
Man-shirts
etc....
So in the meta tag title Seo there will be the info I want

now the men's t-shirt collection I see it through the filter selection in the sidebar of the shop which creates me this url:

https://seashepherdstore.it/collections/uomo?q=tp_:magliette (in italian)

but here the meta tag title seo is:

<title>Collezione Uomo | Sea Shepherd Store– SeaShepherdItalia</title> (in italian)

without the word "t-shirt" ("maglietta" in Italian)