Quiero dedicar más tiempo a mi familia este verano.

Quiero dedicar means I want to dedicate / spend. The verb querer expresses desire or intention, and it is followed by an infinitive: dedicar.

• Quiero dedicar más tiempo... = I want to devote more time...
• Dedico más tiempo... = I devote / am devoting more time...

So quiero dedicar talks about what the speaker wants to do, not necessarily what they are already doing.

Here, dedicar means to devote or to spend in the sense of giving time or attention to something or someone.

So:

• dedicar tiempo a mi familia = to devote time to my family

This is a very common structure in Spanish:

• dedicar tiempo a... = to devote time to...
• dedicar esfuerzo a... = to devote effort to...

The a is required by the verb dedicar in this structure.

You dedicate something to someone:

• dedicar tiempo a mi familia
• dedicar energía a mis estudios
• dedicar recursos al proyecto

So a mi familia means to my family, not just my family.

Más tiempo means more time, while mucho tiempo means a lot of time.

They are similar, but not identical:

• Quiero dedicar más tiempo a mi familia = I want to devote more time to my family.
• Quiero dedicar mucho tiempo a mi familia = I want to devote a lot of time to my family.

In your sentence, the idea is comparative: probably more than before or more than I currently do.

In Spanish, possessive adjectives like mi, tu, su, nuestro usually go before the noun:

• mi familia = my family
• mi casa = my house

That is the normal and most natural pattern.

Forms like la familia mía exist, but they are much less common and usually more emphatic or stylistically marked. A learner should normally use mi familia.

In Spanish, time expressions like este verano, este año, este mes, esta semana usually do not need en.

So Spanish says:

• este verano = this summer
• este año = this year
• esta noche = tonight / this evening

Using en este verano is generally unnatural in standard Spanish for this meaning.

Yes. Spanish word order is flexible, and este verano can move depending on emphasis.

For example:

• Quiero dedicar más tiempo a mi familia este verano.
• Este verano quiero dedicar más tiempo a mi familia.

Both are correct. The second version emphasizes this summer a bit more.

Spanish often leaves out subject pronouns because the verb ending already shows who the subject is.

• quiero = I want

So yo is not necessary.

• Quiero dedicar más tiempo... = normal
• Yo quiero dedicar más tiempo... = also correct, but more emphatic

You might add yo if you want contrast:

• Yo quiero dedicar más tiempo, pero él no.

Grammatically, familia is singular, even though it refers to a group of people.

So you say:

• mi familia es importante = my family is important

Not:

• mi familia son importante

Even though it refers to several people, the noun itself is singular.

Yes, and it is very common.

• dedicar más tiempo a mi familia = to devote more time to my family
• pasar más tiempo con mi familia = to spend more time with my family

Both are correct, but the nuance is slightly different:

• dedicar sounds a bit more intentional or purposeful
• pasar tiempo con sounds more like physically being with them

In everyday conversation, pasar más tiempo con mi familia is extremely natural.

Because after querer, Spanish normally uses an infinitive.

Pattern:

• querer + infinitive

Examples:

• quiero comer = I want to eat
• quiero estudiar = I want to study
• quiero dedicar más tiempo... = I want to devote more time...

This is one of the most important basic patterns in Spanish.

The sentence already works perfectly in Spain.

If you wanted a slightly more everyday alternative, people in Spain might also say:

• Quiero pasar más tiempo con mi familia este verano.

But your original sentence is completely natural in Peninsular Spanish. There is nothing non-Spain about it.